revert Objc method changes

Fix compound indexes for dynamic models

CoreStore.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
     s.name = "CoreStore"
-    s.version = "7.3.1"
-    s.swift_version = "5.3"
+    s.version = "8.0.1"
+    s.swift_version = "5.4"
     s.license = "MIT"
     s.homepage = "https://github.com/JohnEstropia/CoreStore"
     s.documentation_url = "https://JohnEstropia.github.io/CoreStore"
@@ -9,10 +9,10 @@ Pod::Spec.new do |s|
     s.author = { "John Rommel Estropia" => "rommel.estropia@gmail.com" }
     s.source = { :git => "https://github.com/JohnEstropia/CoreStore.git", :tag => s.version.to_s }
 
-    s.ios.deployment_target = "10.0"
-    s.osx.deployment_target = "10.12"
-    s.watchos.deployment_target = "3.0"
-    s.tvos.deployment_target = "10.0"
+    s.ios.deployment_target = "11.0"
+    s.osx.deployment_target = "10.13"
+    s.watchos.deployment_target = "4.0"
+    s.tvos.deployment_target = "11.0"
 
     s.source_files = "Sources", "Sources/**/*.{swift,h,m}"
     s.public_header_files = "Sources/**/*.h"

CoreStoreTests/BridgingTests.m

@@ -191,16 +191,8 @@
     XCTAssertEqualObjects([[sqliteStorage class] storeType], [CSSQLiteStore storeType]);
     XCTAssertEqualObjects([[sqliteStorage class] storeType], NSSQLiteStoreType);
     XCTAssertNil(sqliteStorage.configuration);
-    NSDictionary *storeOptions;
-    if (@available(iOS 11.0, macOS 10.13, tvOS 11.0, *)) {
-        
-        storeOptions = @{ NSSQLitePragmasOption: @{ @"journal_mode": @"WAL" },
-                          NSBinaryStoreInsecureDecodingCompatibilityOption: @YES };
-    }
-    else {
-        
-        storeOptions = @{ NSSQLitePragmasOption: @{ @"journal_mode": @"WAL" }};
-    }
+    NSDictionary *storeOptions = @{ NSSQLitePragmasOption: @{ @"journal_mode": @"WAL" },
+                                    NSBinaryStoreInsecureDecodingCompatibilityOption: @YES };
     XCTAssertEqualObjects(sqliteStorage.storeOptions, storeOptions);
     XCTAssertNil(sqliteError);
 }

CoreStoreTests/ConvenienceTests.swift

@@ -23,13 +23,15 @@
 //  SOFTWARE.
 //
 
+import CoreData
+import XCTest
+
 @testable
 import CoreStore
 
 
 // MARK: - ConvenienceTests
 
-@available(macOS 10.12, *)
 class ConvenienceTests: BaseTestCase {
     
     @objc

CoreStoreTests/DynamicModelTests.swift

@@ -197,7 +197,7 @@ class DynamicModelTests: BaseTestDataTestCase {
                 modelVersion: "V1",
                 entities: [
                     Entity<Animal>("Animal"),
-                    Entity<Dog>("Dog"),
+                    Entity<Dog>("Dog", indexes: [[\Dog.$nickname, \Dog.$age]]),
                     Entity<Person>("Person")
                 ],
                 versionLock: [

CoreStoreTests/FromTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/GroupByTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/IntoTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/ListObserverTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable
@@ -31,7 +32,6 @@ import CoreStore
 
 // MARK: - ListObserverTests
 
-@available(macOS 10.12, *)
 class ListObserverTests: BaseTestDataTestCase {
     
     @objc
@@ -551,7 +551,6 @@ class ListObserverTests: BaseTestDataTestCase {
 
 // MARK: TestListObserver
 
-@available(macOS 10.12, *)
 class TestListObserver: ListSectionObserver {
     
     // MARK: ListObserver

CoreStoreTests/ObjectObserverTests.swift

@@ -31,7 +31,6 @@ import CoreStore
 
 // MARK: - ObjectObserverTests
 
-@available(macOS 10.12, *)
 class ObjectObserverTests: BaseTestDataTestCase {
     
     @objc
@@ -203,7 +202,6 @@ class ObjectObserverTests: BaseTestDataTestCase {
 
 // MARK: TestObjectObserver
 
-@available(macOS 10.12, *)
 class TestObjectObserver: ObjectObserver {
     
     typealias ObjectEntityType = TestEntity1

CoreStoreTests/ObjectPublisherTests.swift

@@ -31,7 +31,6 @@ import CoreStore
 
 // MARK: - ObjectPublisherTests
 
-@available(macOS 10.12, *)
 class ObjectPublisherTests: BaseTestDataTestCase {
 
     @objc

CoreStoreTests/OrderByTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/QueryTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/SectionByTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable
@@ -31,7 +32,6 @@ import CoreStore
 
 //MARK: - SectionByTests
 
-@available(macOS 10.12, *)
 final class SectionByTests: XCTestCase {
     
     @objc
@@ -41,11 +41,14 @@ final class SectionByTests: XCTestCase {
             
             let sectionBy = SectionBy<NSManagedObject>("key")
             XCTAssertEqual(sectionBy.sectionKeyPath, "key")
-            XCTAssertEqual(sectionBy.sectionIndexTransformer("key"), "key")
+            XCTAssertNil(sectionBy.sectionIndexTransformer("key"))
         }
         do {
             
-            let sectionBy = SectionBy<NSManagedObject>("key") { $0.flatMap { "\($0):suffix" } }
+            let sectionBy = SectionBy<NSManagedObject>(
+                "key",
+                sectionIndexTransformer: { $0.flatMap { "\($0):suffix" } }
+            )
             XCTAssertEqual(sectionBy.sectionKeyPath, "key")
             XCTAssertEqual(sectionBy.sectionIndexTransformer("key"), "key:suffix")
             XCTAssertNil(sectionBy.sectionIndexTransformer(nil))

CoreStoreTests/SelectTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/SetupTests.swift

@@ -23,6 +23,9 @@
 //  SOFTWARE.
 //
 
+import CoreData
+import XCTest
+
 @testable
 import CoreStore
 

CoreStoreTests/StorageInterfaceTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable
@@ -83,21 +84,11 @@ final class StorageInterfaceTests: XCTestCase {
         let store = SQLiteStore()
         XCTAssertEqual(type(of: store).storeType, NSSQLiteStoreType)
         XCTAssertNil(store.configuration)
-        if #available(iOS 11.0, macOS 10.13, tvOS 11.0, *) {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"],
-                 NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
-            )
-        }
-        else {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"]] as NSDictionary
-            )
-        }
+        XCTAssertEqual(
+            store.storeOptions as NSDictionary?,
+            [NSSQLitePragmasOption: ["journal_mode": "WAL"],
+             NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
+        )
         
         XCTAssertEqual(store.fileURL, SQLiteStore.defaultFileURL)
         XCTAssertTrue(store.migrationMappingProviders.isEmpty)
@@ -123,21 +114,11 @@ final class StorageInterfaceTests: XCTestCase {
         )
         XCTAssertEqual(type(of: store).storeType, NSSQLiteStoreType)
         XCTAssertEqual(store.configuration, "config1")
-        if #available(iOS 11.0, macOS 10.13, tvOS 11.0, *) {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"],
-                 NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
-            )
-        }
-        else {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"]] as NSDictionary
-            )
-        }
+        XCTAssertEqual(
+            store.storeOptions as NSDictionary?,
+            [NSSQLitePragmasOption: ["journal_mode": "WAL"],
+             NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
+        )
         
         XCTAssertEqual(store.fileURL, fileURL)
         XCTAssertEqual(store.migrationMappingProviders as! [XcodeSchemaMappingProvider], [mappingProvider])
@@ -160,21 +141,11 @@ final class StorageInterfaceTests: XCTestCase {
         )
         XCTAssertEqual(type(of: store).storeType, NSSQLiteStoreType)
         XCTAssertEqual(store.configuration, "config1")
-        if #available(iOS 11.0, macOS 10.13, tvOS 11.0, *) {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"],
-                 NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
-            )
-        }
-        else {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"]] as NSDictionary
-            )
-        }
+        XCTAssertEqual(
+            store.storeOptions as NSDictionary?,
+            [NSSQLitePragmasOption: ["journal_mode": "WAL"],
+             NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
+        )
         
         XCTAssertEqual(store.fileURL.deletingLastPathComponent(), SQLiteStore.defaultRootDirectory)
         XCTAssertEqual(store.fileURL.lastPathComponent, fileName)
@@ -209,21 +180,11 @@ final class StorageInterfaceTests: XCTestCase {
         let store = SQLiteStore.legacy()
         XCTAssertEqual(type(of: store).storeType, NSSQLiteStoreType)
         XCTAssertNil(store.configuration)
-        if #available(iOS 11.0, macOS 10.13, tvOS 11.0, *) {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"],
-                 NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
-            )
-        }
-        else {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"]] as NSDictionary
-            )
-        }
+        XCTAssertEqual(
+            store.storeOptions as NSDictionary?,
+            [NSSQLitePragmasOption: ["journal_mode": "WAL"],
+             NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
+        )
         
         XCTAssertEqual(store.fileURL, SQLiteStore.legacyDefaultFileURL)
         XCTAssertTrue(store.migrationMappingProviders.isEmpty)
@@ -246,21 +207,11 @@ final class StorageInterfaceTests: XCTestCase {
         )
         XCTAssertEqual(type(of: store).storeType, NSSQLiteStoreType)
         XCTAssertEqual(store.configuration, "config1")
-        if #available(iOS 11.0, macOS 10.13, tvOS 11.0, *) {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"],
-                 NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
-            )
-        }
-        else {
-            
-            XCTAssertEqual(
-                store.storeOptions as NSDictionary?,
-                [NSSQLitePragmasOption: ["journal_mode": "WAL"]] as NSDictionary
-            )
-        }
+        XCTAssertEqual(
+            store.storeOptions as NSDictionary?,
+            [NSSQLitePragmasOption: ["journal_mode": "WAL"],
+             NSBinaryStoreInsecureDecodingCompatibilityOption: true] as NSDictionary
+        )
         
         XCTAssertEqual(store.fileURL.deletingLastPathComponent(), SQLiteStore.legacyDefaultRootDirectory)
         XCTAssertEqual(store.fileURL.lastPathComponent, fileName)

CoreStoreTests/TransactionTests.swift

@@ -383,8 +383,6 @@ final class TransactionTests: BaseTestCase {
         }
     }
     
-    
-    @available(macOS 10.12, *)
     @objc
     dynamic func test_ThatSynchronousTransactions_CanCommitWithoutWaitingForMerges() {
         

CoreStoreTests/TweakTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

CoreStoreTests/WhereTests.swift

@@ -23,6 +23,7 @@
 //  SOFTWARE.
 //
 
+import CoreData
 import XCTest
 
 @testable

Demo/Demo.xcodeproj/project.pbxproj

@@ -15,9 +15,9 @@
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-		B566C8E824F9D406001134A1 /* Modern.PokedexDemo.ListView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8E724F9D406001134A1 /* Modern.PokedexDemo.ListView.swift */; };
-		B566C8EA24F9D412001134A1 /* Modern.PokedexDemo.ListViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8E924F9D412001134A1 /* Modern.PokedexDemo.ListViewController.swift */; };
-		B566C8EC24F9D694001134A1 /* Modern.PokedexDemo.ItemCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.ItemCell.swift */; };
+		B566C8E824F9D406001134A1 /* Modern.PokedexDemo.UIKit.ListView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8E724F9D406001134A1 /* Modern.PokedexDemo.UIKit.ListView.swift */; };
+		B566C8EA24F9D412001134A1 /* Modern.PokedexDemo.UIKit.ListViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8E924F9D412001134A1 /* Modern.PokedexDemo.UIKit.ListViewController.swift */; };
+		B566C8EC24F9D694001134A1 /* Modern.PokedexDemo.UIKit.ItemCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.UIKit.ItemCell.swift */; };
 		B566C8EE24FA1EA3001134A1 /* Modern.PokedexDemo.Details.swift in Sources */ = {isa = PBXBuildFile; fileRef = B566C8ED24FA1EA3001134A1 /* Modern.PokedexDemo.Details.swift */; };
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@@ -68,7 +68,7 @@
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 		B5A391A224E8F01F00E7E8BD /* ⭐️Modern.ColorsDemo.UIKit.ListViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391A124E8F01F00E7E8BD /* ⭐️Modern.ColorsDemo.UIKit.ListViewController.swift */; };
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-		B5A391A624E8F4EA00E7E8BD /* ⭐️Modern.ColorsDemo.MainView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391A524E8F4EA00E7E8BD /* ⭐️Modern.ColorsDemo.MainView.swift */; };
+		B5A391A624E8F4EA00E7E8BD /* Modern.ColorsDemo.MainView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391A524E8F4EA00E7E8BD /* Modern.ColorsDemo.MainView.swift */; };
 		B5A391AA24E9104300E7E8BD /* Modern.ColorsDemo.UIKit.ItemCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391A924E9104300E7E8BD /* Modern.ColorsDemo.UIKit.ItemCell.swift */; };
 		B5A391AC24E9143B00E7E8BD /* Modern.ColorsDemo.UIKit.DetailView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391AB24E9143B00E7E8BD /* Modern.ColorsDemo.UIKit.DetailView.swift */; };
 		B5A391AE24E9150F00E7E8BD /* ⭐️Modern.ColorsDemo.UIKit.DetailViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A391AD24E9150F00E7E8BD /* ⭐️Modern.ColorsDemo.UIKit.DetailViewController.swift */; };
@@ -97,6 +97,7 @@
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+		B5C795B625D8EE2B00BDACC1 /* Modern.PokedexDemo.UIKit.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5C795B525D8EE2B00BDACC1 /* Modern.PokedexDemo.UIKit.swift */; };
 		B5D6F1F8250E07FD00DF5D2F /* Advanced.EvolutionDemo.V1.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5D6F1F7250E07FD00DF5D2F /* Advanced.EvolutionDemo.V1.swift */; };
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@@ -133,9 +134,9 @@
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-		B566C8E724F9D406001134A1 /* Modern.PokedexDemo.ListView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.ListView.swift; sourceTree = "<group>"; };
-		B566C8E924F9D412001134A1 /* Modern.PokedexDemo.ListViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.ListViewController.swift; sourceTree = "<group>"; };
-		B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.ItemCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.ItemCell.swift; sourceTree = "<group>"; };
+		B566C8E724F9D406001134A1 /* Modern.PokedexDemo.UIKit.ListView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.UIKit.ListView.swift; sourceTree = "<group>"; };
+		B566C8E924F9D412001134A1 /* Modern.PokedexDemo.UIKit.ListViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.UIKit.ListViewController.swift; sourceTree = "<group>"; };
+		B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.UIKit.ItemCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.UIKit.ItemCell.swift; sourceTree = "<group>"; };
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@@ -185,7 +186,7 @@
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-		B5A391A524E8F4EA00E7E8BD /* ⭐️Modern.ColorsDemo.MainView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "⭐️Modern.ColorsDemo.MainView.swift"; sourceTree = "<group>"; };
+		B5A391A524E8F4EA00E7E8BD /* Modern.ColorsDemo.MainView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.ColorsDemo.MainView.swift; sourceTree = "<group>"; };
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@@ -214,6 +215,7 @@
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 		B5A5440C2504949C000DC5E3 /* Advanced.EvolutionDemo.V4.Creature.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Advanced.EvolutionDemo.V4.Creature.swift; sourceTree = "<group>"; };
 		B5C18F3225138700001BEFB3 /* Advanced.EvolutionDemo.ProgressView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Advanced.EvolutionDemo.ProgressView.swift; sourceTree = "<group>"; };
+		B5C795B525D8EE2B00BDACC1 /* Modern.PokedexDemo.UIKit.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modern.PokedexDemo.UIKit.swift; sourceTree = "<group>"; };
 		B5D6F1F7250E07FD00DF5D2F /* Advanced.EvolutionDemo.V1.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Advanced.EvolutionDemo.V1.swift; sourceTree = "<group>"; };
 		B5D6F1FB250E0B1700DF5D2F /* Advanced.EvolutionDemo.V2.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Advanced.EvolutionDemo.V2.swift; sourceTree = "<group>"; };
 		B5D6F1FD250E0B3F00DF5D2F /* Advanced.EvolutionDemo.GeologicalPeriod.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Advanced.EvolutionDemo.GeologicalPeriod.swift; sourceTree = "<group>"; };
@@ -412,7 +414,7 @@
 			children = (
 				B5A3918E24E7E06500E7E8BD /* Modern.ColorsDemo.swift */,
 				B5A3919724E7E67000E7E8BD /* Modern.ColorsDemo.Filter.swift */,
-				B5A391A524E8F4EA00E7E8BD /* ⭐️Modern.ColorsDemo.MainView.swift */,
+				B5A391A524E8F4EA00E7E8BD /* Modern.ColorsDemo.MainView.swift */,
 				B5A3919C24E8EE9000E7E8BD /* ⭐️UIKit */,
 				B5A3919B24E8EE8100E7E8BD /* ⭐️SwiftUI */,
 				B5A3919024E7E0B000E7E8BD /* Models */,
@@ -458,9 +460,7 @@
 				B5A391B024E96AF600E7E8BD /* Modern.PokedexDemo.swift */,
 				B531EFEA24EB5ECD005F247D /* ⭐️Modern.PokedexDemo.Service.swift */,
 				B531EFEC24EB7453005F247D /* Modern.PokedexDemo.MainView.swift */,
-				B566C8E724F9D406001134A1 /* Modern.PokedexDemo.ListView.swift */,
-				B566C8E924F9D412001134A1 /* Modern.PokedexDemo.ListViewController.swift */,
-				B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.ItemCell.swift */,
+				B5C795B425D8EE1A00BDACC1 /* ⭐️UIKit */,
 				B5A391B224E96B7400E7E8BD /* ⭐️Models */,
 			);
 			path = "⭐️PokedexDemo";
@@ -549,6 +549,17 @@
 			name = Models;
 			sourceTree = "<group>";
 		};
+		B5C795B425D8EE1A00BDACC1 /* ⭐️UIKit */ = {
+			isa = PBXGroup;
+			children = (
+				B5C795B525D8EE2B00BDACC1 /* Modern.PokedexDemo.UIKit.swift */,
+				B566C8E724F9D406001134A1 /* Modern.PokedexDemo.UIKit.ListView.swift */,
+				B566C8E924F9D412001134A1 /* Modern.PokedexDemo.UIKit.ListViewController.swift */,
+				B566C8EB24F9D694001134A1 /* Modern.PokedexDemo.UIKit.ItemCell.swift */,
+			);
+			name = "⭐️UIKit";
+			sourceTree = "<group>";
+		};
 		B5D6F1F9250E08D200DF5D2F /* V1 */ = {
 			isa = PBXGroup;
 			children = (
@@ -704,6 +715,7 @@
 				B5A543ED24FB84BE000DC5E3 /* Classic.ColorsDemo.MainView.swift in Sources */,
 				B5A543DD24FB78F9000DC5E3 /* Classic.ColorsDemo.Palette.swift in Sources */,
 				B5A3919824E7E67000E7E8BD /* Modern.ColorsDemo.Filter.swift in Sources */,
+				B5C795B625D8EE2B00BDACC1 /* Modern.PokedexDemo.UIKit.swift in Sources */,
 				B5A3919224E7E0C600E7E8BD /* Modern.ColorsDemo.Palette.swift in Sources */,
 				B5A3919E24E8EEB600E7E8BD /* Modern.ColorsDemo.SwiftUI.swift in Sources */,
 				B5A391A024E8F00A00E7E8BD /* Modern.ColorsDemo.UIKit.swift in Sources */,
@@ -711,16 +723,16 @@
 				B5A3916024E6925900E7E8BD /* Modern.PlacemarksDemo.MapView.swift in Sources */,
 				B5A3916524E698C700E7E8BD /* Modern.PlacemarksDemo.Place.swift in Sources */,
 				B566C8EE24FA1EA3001134A1 /* Modern.PokedexDemo.Details.swift in Sources */,
-				B566C8EC24F9D694001134A1 /* Modern.PokedexDemo.ItemCell.swift in Sources */,
-				B566C8E824F9D406001134A1 /* Modern.PokedexDemo.ListView.swift in Sources */,
-				B566C8EA24F9D412001134A1 /* Modern.PokedexDemo.ListViewController.swift in Sources */,
+				B566C8EC24F9D694001134A1 /* Modern.PokedexDemo.UIKit.ItemCell.swift in Sources */,
+				B566C8E824F9D406001134A1 /* Modern.PokedexDemo.UIKit.ListView.swift in Sources */,
+				B566C8EA24F9D412001134A1 /* Modern.PokedexDemo.UIKit.ListViewController.swift in Sources */,
 				B531EFED24EB7453005F247D /* Modern.PokedexDemo.MainView.swift in Sources */,
 				B5A3918C24E7B44B00E7E8BD /* Modern.TimeZonesDemo.ItemView.swift in Sources */,
 				B5A3918A24E7AD1800E7E8BD /* Modern.TimeZonesDemo.ListView.swift in Sources */,
 				B5A3918624E7A54A00E7E8BD /* Modern.TimeZonesDemo.TimeZone.swift in Sources */,
 				B5A543EB24FB84AF000DC5E3 /* ⭐️Classic.ColorsDemo.DetailViewController.swift in Sources */,
 				B5A543F124FB84DD000DC5E3 /* ⭐️Classic.ColorsDemo.ListViewController.swift in Sources */,
-				B5A391A624E8F4EA00E7E8BD /* ⭐️Modern.ColorsDemo.MainView.swift in Sources */,
+				B5A391A624E8F4EA00E7E8BD /* Modern.ColorsDemo.MainView.swift in Sources */,
 				B5A3916224E697BA00E7E8BD /* ⭐️Modern.PlacemarksDemo.MainView.swift in Sources */,
 				B5A391B424E96C0A00E7E8BD /* ⭐️Modern.PokedexDemo.Form.swift in Sources */,
 				B531EFE924EB5A53005F247D /* ⭐️Modern.PokedexDemo.PokedexEntry.swift in Sources */,

Demo/⭐️Sources/Helpers/InstructionsView.swift

@@ -20,8 +20,8 @@ struct InstructionsView: View {
     
     var body: some View {
         ZStack(alignment: .center) {
-            Color.white
-                .cornerRadius(10)
+            RoundedRectangle(cornerRadius: 10, style: .continuous)
+                .fill(Color.white)
                 .shadow(color: Color(.sRGB, white: 0.5, opacity: 0.3), radius: 2, x: 1, y: 1)
             VStack(alignment: .leading, spacing: 3) {
                 ForEach(self.rows, id: \.header) { row in

Demo/⭐️Sources/Helpers/Menu/Menu.MainView.swift

@@ -73,7 +73,9 @@ extension Menu {
                             title: "Pokedex API",
                             subtitle: "Importing JSON data from external source",
                             destination: {
-                                Modern.PokedexDemo.MainView()
+                                Modern.PokedexDemo.MainView(
+                                    listView: Modern.PokedexDemo.UIKit.ListView.init
+                                )
                             }
                         )
                     }

Demo/⭐️Sources/⭐️Demos/⭐️Advanced/⭐️EvolutionDemo/Advanced.EvolutionDemo.ProgressView.swift

@@ -45,17 +45,16 @@ extension Advanced.EvolutionDemo {
                         .padding(.horizontal)
                     GeometryReader { geometry in
                         ZStack(alignment: .leading) {
-                            Color.gray
-                                .opacity(0.2)
+                            RoundedRectangle(cornerRadius: 4, style: .continuous)
+                                .fill(Color.gray.opacity(0.2))
                                 .frame(width: geometry.size.width, height: 8)
-                                .cornerRadius(4.0)
-                            Color.blue
+                            RoundedRectangle(cornerRadius: 4, style: .continuous)
+                                .fill(Color.blue)
                                 .frame(
                                     width: geometry.size.width
                                         * self.progressObserver.fractionCompleted,
                                     height: 8
                                 )
-                                .cornerRadius(4.0)
                         }
                     }
                     .fixedSize(horizontal: false, vertical: true)

Demo/⭐️Sources/⭐️Demos/⭐️Classic/⭐️ColorsDemo/Classic.ColorsDemo.xcdatamodeld/ColorsDemo.xcdatamodel/contents

@@ -1,12 +1,15 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="16119" systemVersion="19F101" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="17709" systemVersion="20C5048l" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
     <entity name="Palette" representedClassName="Classic_ColorsDemo_Palette" syncable="YES">
         <attribute name="brightness" attributeType="Float" defaultValueString="0.0" usesScalarValueType="YES"/>
         <attribute name="colorGroup" optional="YES" transient="YES" attributeType="String"/>
         <attribute name="hue" attributeType="Float" defaultValueString="0.0" usesScalarValueType="YES"/>
         <attribute name="saturation" attributeType="Float" defaultValueString="0.0" usesScalarValueType="YES"/>
+        <fetchedProperty name="testFetchProperty" optional="YES">
+            <fetchRequest name="fetchedPropertyFetchRequest" entity="Palette"/>
+        </fetchedProperty>
     </entity>
     <elements>
-        <element name="Palette" positionX="-63" positionY="-18" width="128" height="103"/>
+        <element name="Palette" positionX="-63" positionY="-18" width="128" height="110"/>
     </elements>
 </model>

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/Modern.ColorsDemo.MainView.swift

@@ -13,12 +13,6 @@ extension Modern.ColorsDemo {
 
     struct MainView<ListView: View, DetailView: View>: View {
         
-        /**
-         ⭐️ Sample 1: Setting a sectioned `ListPublisher` declared as an `@ObservedObject`
-         */
-        @ObservedObject
-        private var listPublisher: ListPublisher<Modern.ColorsDemo.Palette>
-        
         // MARK: Internal
         
         init(
@@ -30,38 +24,24 @@ extension Modern.ColorsDemo {
             
             self.listView = listView
             self.detailView = detailView
-            self.listPublisher = Modern.ColorsDemo.palettesPublisher
-            self._filter = Binding(
-                get: { Modern.ColorsDemo.filter },
-                set: { Modern.ColorsDemo.filter = $0 }
-            )
         }
         
         
         // MARK: View
         
         var body: some View {
-            let detailView: AnyView
-            if let selectedPalette = self.selectedPalette {
-                
-                detailView = AnyView(
-                    self.detailView(selectedPalette)
-                )
-            }
-            else {
-                
-                detailView = AnyView(EmptyView())
-            }
-            let listPublisher = self.listPublisher
             return VStack(spacing: 0) {
-                self.listView(listPublisher, { self.selectedPalette = $0 })
+                self.listView(self.$palettes, { self.selectedPalette = $0 })
                     .navigationBarTitle(
-                        Text("Colors (\(listPublisher.snapshot.numberOfItems) objects)")
+                        Text("Colors (\(self.palettes.count) objects)")
                     )
                     .frame(minHeight: 0, maxHeight: .infinity)
-                detailView
-                    .edgesIgnoringSafeArea(.all)
-                    .frame(minHeight: 0, maxHeight: .infinity)
+                self.selectedPalette.map {
+                    
+                    self.detailView($0)
+                        .edgesIgnoringSafeArea(.all)
+                        .frame(minHeight: 0, maxHeight: .infinity)
+                }
             }
             .navigationBarItems(
                 leading: HStack {
@@ -91,6 +71,9 @@ extension Modern.ColorsDemo {
         
         // MARK: Private
         
+        @ListState(Modern.ColorsDemo.palettesPublisher)
+        private var palettes: ListSnapshot
+        
         private let listView: (
             _ listPublisher: ListPublisher<Modern.ColorsDemo.Palette>,
             _ onPaletteTapped: @escaping (ObjectPublisher<Modern.ColorsDemo.Palette>) -> Void
@@ -103,12 +86,13 @@ extension Modern.ColorsDemo {
         @State
         private var selectedPalette: ObjectPublisher<Modern.ColorsDemo.Palette>?
         
-        @Binding
-        private var filter: Modern.ColorsDemo.Filter
+        @State
+        private var filter: Modern.ColorsDemo.Filter = Modern.ColorsDemo.filter
         
         private func changeFilter() {
             
             Modern.ColorsDemo.filter = Modern.ColorsDemo.filter.next()
+            self.filter = Modern.ColorsDemo.filter
         }
         
         private func clearColors() {
@@ -118,6 +102,7 @@ extension Modern.ColorsDemo {
 
                     try transaction.deleteAll(From<Modern.ColorsDemo.Palette>())
                 },
+                sourceIdentifier: TransactionSource.clear,
                 completion: { _ in }
             )
         }
@@ -129,6 +114,7 @@ extension Modern.ColorsDemo {
 
                     _ = transaction.create(Into<Modern.ColorsDemo.Palette>())
                 },
+                sourceIdentifier: TransactionSource.add,
                 completion: { _ in }
             )
         }
@@ -143,6 +129,7 @@ extension Modern.ColorsDemo {
                         palette.setRandomHue()
                     }
                 },
+                sourceIdentifier: TransactionSource.shuffle,
                 completion: { _ in }
             )
         }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/Modern.ColorsDemo.UIKit.DetailView.swift

@@ -30,14 +30,19 @@ extension Modern.ColorsDemo.UIKit {
             return UIViewControllerType(self.palette)
         }
 
-        func updateUIViewController(_ uiViewController: UIViewControllerType, context: Self.Context) {}
+        func updateUIViewController(_ uiViewController: UIViewControllerType, context: Self.Context) {
+            
+            uiViewController.palette = Modern.ColorsDemo.dataStack.monitorObject(
+                self.palette.object!
+            )
+        }
 
         static func dismantleUIViewController(_ uiViewController: UIViewControllerType, coordinator: Void) {}
         
         
         // MARK: Private
         
-        private let palette: ObjectPublisher<Modern.ColorsDemo.Palette>
+        private var palette: ObjectPublisher<Modern.ColorsDemo.Palette>
     }
 }
 

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/Modern.ColorsDemo.swift

@@ -2,6 +2,7 @@
 // Demo
 // Copyright © 2020 John Rommel Estropia, Inc. All rights reserved.
 
+import SwiftUI
 import CoreStore
 
 // MARK: - Modern
@@ -45,7 +46,10 @@ extension Modern {
         
         static let palettesPublisher: ListPublisher<Modern.ColorsDemo.Palette> = Modern.ColorsDemo.dataStack.publishList(
             From<Modern.ColorsDemo.Palette>()
-                .sectionBy(\.$colorGroup)
+                .sectionBy(
+                    \.$colorGroup,
+                    sectionIndexTransformer: { $0?.first?.uppercased() }
+                )
                 .where(Modern.ColorsDemo.filter.whereClause())
                 .orderBy(.ascending(\.$hue))
         )
@@ -56,11 +60,27 @@ extension Modern {
                 
                 try! Modern.ColorsDemo.palettesPublisher.refetch(
                     From<Modern.ColorsDemo.Palette>()
-                        .sectionBy(\.$colorGroup)
+                        .sectionBy(
+                            \.$colorGroup,
+                            sectionIndexTransformer: { $0?.first?.uppercased() }
+                        )
                         .where(self.filter.whereClause())
-                        .orderBy(.ascending(\.$hue))
+                        .orderBy(.ascending(\.$hue)),
+                    sourceIdentifier: TransactionSource.refetch
                 )
             }
         }
+        
+        
+        // MARK: - TransactionSource
+        
+        enum TransactionSource {
+            
+            case add
+            case delete
+            case shuffle
+            case clear
+            case refetch
+        }
     }
 }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.SwiftUI.DetailView.swift

@@ -15,10 +15,10 @@ extension Modern.ColorsDemo.SwiftUI {
     struct DetailView: View {
         
         /**
-         ⭐️ Sample 1: Setting an `ObjectPublisher` declared as an `@ObservedObject`
+         ⭐️ Sample 1: Using a `ObjectState` to observe object changes. Note that the `ObjectSnapshot` is always `Optional`
          */
-        @ObservedObject
-        private var palette: ObjectPublisher<Modern.ColorsDemo.Palette>
+        @ObjectState
+        private var palette: ObjectSnapshot<Modern.ColorsDemo.Palette>?
         
         /**
          ⭐️ Sample 2: Setting properties that can be binded to controls (`Slider` in this case) by creating custom `@Binding` instances that updates the store when the values change.
@@ -34,7 +34,7 @@ extension Modern.ColorsDemo.SwiftUI {
 
         init(_ palette: ObjectPublisher<Modern.ColorsDemo.Palette>) {
 
-            self.palette = palette
+            self._palette = .init(palette)
             self._hue = Binding(
                 get: { palette.hue ?? 0 },
                 set: { percentage in
@@ -84,56 +84,50 @@ extension Modern.ColorsDemo.SwiftUI {
         
         var body: some View {
             
-            guard let snapshot = self.palette.snapshot else {
+            if let palette = self.palette {
                 
-                return AnyView(EmptyView())
-            }
-            return AnyView(
-                GeometryReader { geometry in
-                    ZStack(alignment: .bottom) {
-                        Color(snapshot.$color)
-                        ZStack {
-                            Color.white
-                                .cornerRadius(10)
-                                .shadow(color: Color(.sRGB, white: 0.5, opacity: 0.3), radius: 2, x: 1, y: 1)
-                            VStack(alignment: .leading, spacing: 10) {
-                                HStack {
-                                    Text("H: \(Int(snapshot.$hue * 359))°")
-                                        .frame(width: 80)
-                                    Slider(
-                                        value: self.$hue,
-                                        in: 0 ... 1,
-                                        step: 1 / 359
-                                    )
-                                }
-                                HStack {
-                                    Text("S: \(Int(snapshot.$saturation * 100))%")
-                                        .frame(width: 80)
-                                    Slider(
-                                        value: self.$saturation,
-                                        in: 0 ... 1,
-                                        step: 1 / 100
-                                    )
-                                }
-                                HStack {
-                                    Text("B: \(Int(snapshot.$brightness * 100))%")
-                                        .frame(width: 80)
-                                    Slider(
-                                        value: self.$brightness,
-                                        in: 0 ... 1,
-                                        step: 1 / 100
-                                    )
-                                }
+                ZStack(alignment: .center) {
+                    Color(palette.$color)
+                    ZStack {
+                        RoundedRectangle(cornerRadius: 10, style: .continuous)
+                            .fill(Color.white)
+                            .shadow(color: Color(.sRGB, white: 0.5, opacity: 0.3), radius: 2, x: 1, y: 1)
+                        VStack(alignment: .leading, spacing: 10) {
+                            HStack {
+                                Text("H: \(Int(palette.$hue * 359))°")
+                                    .frame(width: 80)
+                                Slider(
+                                    value: self.$hue,
+                                    in: 0 ... 1,
+                                    step: 1 / 359
+                                )
+                            }
+                            HStack {
+                                Text("S: \(Int(palette.$saturation * 100))%")
+                                    .frame(width: 80)
+                                Slider(
+                                    value: self.$saturation,
+                                    in: 0 ... 1,
+                                    step: 1 / 100
+                                )
+                            }
+                            HStack {
+                                Text("B: \(Int(palette.$brightness * 100))%")
+                                    .frame(width: 80)
+                                Slider(
+                                    value: self.$brightness,
+                                    in: 0 ... 1,
+                                    step: 1 / 100
+                                )
                             }
-                            .foregroundColor(Color(.sRGB, white: 0, opacity: 0.8))
-                            .padding()
                         }
-                        .fixedSize(horizontal: false, vertical: true)
+                        .foregroundColor(Color(.sRGB, white: 0, opacity: 0.8))
                         .padding()
-                        .padding(geometry.safeAreaInsets)
                     }
+                    .fixedSize(horizontal: false, vertical: true)
+                    .padding()
                 }
-            )
+            }
         }
     }
 }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.SwiftUI.ItemView.swift

@@ -14,36 +14,34 @@ extension Modern.ColorsDemo.SwiftUI {
     struct ItemView: View {
         
         /**
-         ⭐️ Sample 1: Setting an `ObjectPublisher` declared as an `@ObservedObject`
+         ⭐️ Sample 1: Using a `ObjectState` to observe object changes. Note that the `ObjectSnapshot` is always `Optional`
          */
-        @ObservedObject
-        private var palette: ObjectPublisher<Modern.ColorsDemo.Palette>
-        
-        
-        // MARK: Internal
+        @ObjectState
+        private var palette: ObjectSnapshot<Modern.ColorsDemo.Palette>?
         
+        /**
+         ⭐️ Sample 2: Initializing a `ObjectState` from an existing `ObjectPublisher`
+         */
         internal init(_ palette: ObjectPublisher<Modern.ColorsDemo.Palette>) {
             
-            self.palette = palette
+            self._palette = .init(palette)
         }
         
-        
-        // MARK: View
-
+        /**
+         ⭐️ Sample 3: Readding values directly from the `ObjectSnapshot`
+         */
         var body: some View {
             
-            guard let palette = self.palette.snapshot else {
+            if let palette = self.palette {
                 
-                return AnyView(EmptyView())
-            }
-            return AnyView(
                 Color(palette.$color).overlay(
                     Text(palette.$colorText)
                         .foregroundColor(palette.$brightness > 0.6 ? .black : .white)
                         .padding(),
                     alignment: .leading
                 )
-            )
+                .animation(.default)
+            }
         }
     }
 }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.SwiftUI.ListView.swift

@@ -5,7 +5,6 @@
 import CoreStore
 import SwiftUI
 
-
 // MARK: - Modern.ColorsDemo.SwiftUI
 
 extension Modern.ColorsDemo.SwiftUI {
@@ -15,53 +14,58 @@ extension Modern.ColorsDemo.SwiftUI {
     struct ListView: View {
         
         /**
-         ⭐️ Sample 1: Setting a sectioned `ListPublisher` declared as an `@ObservedObject`
+         ⭐️ Sample 1: Using a `ListState` to observe list changes
          */
-        @ObservedObject
-        private var listPublisher: ListPublisher<Modern.ColorsDemo.Palette>
+        @ListState
+        private var palettes: ListSnapshot<Modern.ColorsDemo.Palette>
         
         /**
-         ⭐️ Sample 2: Assigning sections and items of the `ListPublisher` to corresponding `View`s
+         ⭐️ Sample 2: Initializing a `ListState` from an existing `ListPublisher`
          */
-         var body: some View {
-            let listSnapshot = self.listPublisher.snapshot
-            return List {
-                ForEach(listSnapshot.sectionIDs, id: \.self) { (sectionID) in
-                    Section(header: Text(sectionID)) {
-                        ForEach(listSnapshot.items(inSectionWithID: sectionID), id: \.self) { palette in
+        init(
+            listPublisher: ListPublisher<Modern.ColorsDemo.Palette>,
+            onPaletteTapped: @escaping (ObjectPublisher<Modern.ColorsDemo.Palette>) -> Void
+        ) {
+            
+            self._palettes = .init(listPublisher)
+            self.onPaletteTapped = onPaletteTapped
+        }
+        
+        /**
+         ⭐️ Sample 3: Assigning sections and items of the `ListSnapshot` to corresponding `View`s by using the correct `ForEach` overloads.
+         */
+        var body: some View {
+            
+            List {
+                
+                ForEach(sectionIn: self.palettes) { section in
+                    
+                    Section(header: Text(section.sectionID)) {
+                        
+                        ForEach(objectIn: section) { palette in
+                            
                             Button(
                                 action: {
+                                    
                                     self.onPaletteTapped(palette)
                                 },
                                 label: {
+                                    
                                     Modern.ColorsDemo.SwiftUI.ItemView(palette)
                                 }
                             )
                             .listRowInsets(.init())
                         }
                         .onDelete { itemIndices in
-
-                            self.deleteColors(at: itemIndices, in: sectionID)
+                            
+                            self.deleteColors(at: itemIndices, in: section.sectionID)
                         }
                     }
                 }
-                GeometryReader { geometry in
-                    Spacer(minLength: geometry.safeAreaInsets.bottom)
-                }
             }
+            .animation(.default)
             .listStyle(PlainListStyle())
-         }
-        
-        
-        // MARK: Internal
-        
-        init(
-            listPublisher: ListPublisher<Modern.ColorsDemo.Palette>,
-            onPaletteTapped: @escaping (ObjectPublisher<Modern.ColorsDemo.Palette>) -> Void
-        ) {
-            
-            self.listPublisher = listPublisher
-            self.onPaletteTapped = onPaletteTapped
+            .edgesIgnoringSafeArea([])
         }
         
         
@@ -71,7 +75,7 @@ extension Modern.ColorsDemo.SwiftUI {
         
         private func deleteColors(at indices: IndexSet, in sectionID: String) {
             
-            let objectIDsToDelete = self.listPublisher.snapshot.itemIDs(
+            let objectIDsToDelete = self.palettes.itemIDs(
                 inSectionWithID: sectionID,
                 atIndices: indices
             )

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.UIKit.DetailViewController.swift

@@ -40,6 +40,15 @@ extension Modern.ColorsDemo.UIKit {
         /**
          ⭐️ Sample 3: We can end monitoring updates anytime. `removeObserver()` was called here for illustration purposes only. `ObjectMonitor`s safely remove deallocated observers automatically.
          */
+        var palette: ObjectMonitor<Modern.ColorsDemo.Palette> {
+            
+            didSet {
+                
+                oldValue.removeObserver(self)
+                self.startMonitoringObject()
+            }
+        }
+        
         deinit {
             
             self.palette.removeObserver(self)
@@ -82,7 +91,8 @@ extension Modern.ColorsDemo.UIKit {
         func objectMonitor(
             _ monitor: ObjectMonitor<Modern.ColorsDemo.Palette>,
             didUpdateObject object: Modern.ColorsDemo.Palette,
-            changedPersistentKeys: Set<KeyPathString>
+            changedPersistentKeys: Set<KeyPathString>,
+            sourceIdentifier: Any?
         ) {
             
             self.reloadPaletteInfo(object, changedKeys: changedPersistentKeys)
@@ -183,9 +193,8 @@ extension Modern.ColorsDemo.UIKit {
                             equalTo: view.safeAreaLayoutGuide.leadingAnchor,
                             constant: 10
                         ),
-                        containerView.bottomAnchor.constraint(
-                            equalTo: view.safeAreaLayoutGuide.bottomAnchor,
-                            constant: -10
+                        containerView.centerYAnchor.constraint(
+                            equalTo: view.safeAreaLayoutGuide.centerYAnchor
                         ),
                         containerView.trailingAnchor.constraint(
                             equalTo: view.safeAreaLayoutGuide.trailingAnchor,
@@ -223,8 +232,6 @@ extension Modern.ColorsDemo.UIKit {
         
         // MARK: Private
         
-        private let palette: ObjectMonitor<Modern.ColorsDemo.Palette>
-        
         @available(*, unavailable)
         required init?(coder: NSCoder) {
             

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️ColorsDemo/⭐️Modern.ColorsDemo.UIKit.ListViewController.swift

@@ -15,9 +15,9 @@ extension Modern.ColorsDemo.UIKit {
     final class ListViewController: UITableViewController {
         
         /**
-         ⭐️ Sample 1: Setting up a `DiffableDataSource.TableViewAdapter` that will manage tableView snapshot updates automatically. We can use the built-in `DiffableDataSource.TableViewAdapter` type directly, but in our case we want to enabled `UITableView` cell deletions so we create a custom subclass `DeletionEnabledDataSource` (see declaration below).
+         ⭐️ Sample 1: Setting up a `DiffableDataSource.TableViewAdapter` that will manage tableView snapshot updates automatically. We can use the built-in `DiffableDataSource.TableViewAdapter` type directly, but in our case we want to enabled `UITableView` cell deletions so we create a custom subclass `CustomDataSource` (see declaration below).
          */
-        private lazy var dataSource: DiffableDataSource.TableViewAdapter<Modern.ColorsDemo.Palette> = DeletionEnabledDataSource(
+        private lazy var dataSource: DiffableDataSource.TableViewAdapter<Modern.ColorsDemo.Palette> = CustomDataSource(
             tableView: self.tableView,
             dataStack: Modern.ColorsDemo.dataStack,
             cellProvider: { (tableView, indexPath, palette) in
@@ -32,21 +32,26 @@ extension Modern.ColorsDemo.UIKit {
         )
         
         /**
-         ⭐️ Sample 2: Once the views are created, we can start binding `ListPublisher` updates to the `DiffableDataSource`. We typically call this at the end of `viewDidLoad`. Note that the `addObserver`'s closure argument will only be called on the succeeding updates, so to immediately display the current values, we need to call `dataSource.apply()` once.
+         ⭐️ Sample 2: Once the views are created, we can start binding `ListPublisher` updates to the `DiffableDataSource`. We typically call this at the end of `viewDidLoad`. Note that the `addObserver`'s closure argument will only be called on the succeeding updates, so to immediately display the current values, we need to call `dataSource.apply()` once. This example inspects the optional `transactionSource` to determine the source of the update which is helpful for debugging or for fine-tuning animations.
          */
         private func startObservingList() {
             
-            self.listPublisher.addObserver(self) { (listPublisher) in
+            let dataSource = self.dataSource
+            self.listPublisher.addObserver(self, notifyInitial: true) { (listPublisher, transactionSource) in
                 
-                self.dataSource.apply(
-                    listPublisher.snapshot,
-                    animatingDifferences: true
-                )
+                switch transactionSource as? Modern.ColorsDemo.TransactionSource {
+                    
+                case .add,
+                     .delete,
+                     .shuffle,
+                     .clear:
+                    dataSource.apply(listPublisher.snapshot, animatingDifferences: true)
+                    
+                case nil,
+                     .refetch:
+                    dataSource.apply(listPublisher.snapshot, animatingDifferences: false)
+                }
             }
-            self.dataSource.apply(
-                listPublisher.snapshot,
-                animatingDifferences: false
-            )
         }
         
         /**
@@ -58,9 +63,11 @@ extension Modern.ColorsDemo.UIKit {
         }
 
         /**
-         ⭐️ Sample 4: This is the custom `DiffableDataSource.TableViewAdapter` subclass we wrote that enabled swipe-to-delete gestures on the `UITableView`.
+         ⭐️ Sample 4: This is the custom `DiffableDataSource.TableViewAdapter` subclass we wrote that enabled swipe-to-delete gestures and section index titles on the `UITableView`.
          */
-        final class DeletionEnabledDataSource: DiffableDataSource.TableViewAdapter<Modern.ColorsDemo.Palette> {
+        final class CustomDataSource: DiffableDataSource.TableViewAdapter<Modern.ColorsDemo.Palette> {
+            
+            // MARK: UITableViewDataSource
 
             override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
 
@@ -76,6 +83,7 @@ extension Modern.ColorsDemo.UIKit {
 
                             transaction.delete(objectIDs: [itemID])
                         },
+                        sourceIdentifier: Modern.ColorsDemo.TransactionSource.delete,
                         completion: { _ in }
                     )
 
@@ -83,6 +91,16 @@ extension Modern.ColorsDemo.UIKit {
                     break
                 }
             }
+            
+            override func sectionIndexTitles(for tableView: UITableView) -> [String]? {
+                
+                return self.sectionIndexTitlesForAllSections().compactMap({ $0 })
+            }
+            
+            override func tableView(_ tableView: UITableView, sectionForSectionIndexTitle title: String, at index: Int) -> Int {
+                
+                return index
+            }
         }
         
         

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PlacemarksDemo/⭐️Modern.PlacemarksDemo.MainView.swift

@@ -25,7 +25,7 @@ extension Modern.PlacemarksDemo {
             Modern.PlacemarksDemo.dataStack.perform(
                 asynchronous: { (transaction) in
                     
-                    let place = self.place.asEditable(in: transaction)
+                    let place = self.$place?.asEditable(in: transaction)
                     place?.annotation = .init(coordinate: coordinate)
                 },
                 completion: { _ in }
@@ -42,7 +42,7 @@ extension Modern.PlacemarksDemo {
             _ = try? Modern.PlacemarksDemo.dataStack.perform(
                 synchronous: {  (transaction) in
                     
-                    let place = self.place.asEditable(in: transaction)
+                    let place = self.$place?.asEditable(in: transaction)
                     place?.setRandomLocation()
                 }
             )
@@ -71,22 +71,25 @@ extension Modern.PlacemarksDemo {
 
         // MARK: Internal
 
-        @ObservedObject
-        var place: ObjectPublisher<Modern.PlacemarksDemo.Place>
+        @ObjectState(Modern.PlacemarksDemo.placePublisher)
+        var place: ObjectSnapshot<Modern.PlacemarksDemo.Place>?
         
         init() {
             
-            self.place = Modern.PlacemarksDemo.placePublisher
-            self.sinkCancellable = self.place.sink(
+            self.sinkCancellable = self.$place?.reactive.snapshot().sink(
                 receiveCompletion: { _ in
                     
                     // Deleted, do nothing
                 },
                 receiveValue: { [self] (snapshot) in
                     
+                    guard let snapshot = snapshot else {
+                        
+                        return
+                    }
                     self.geocoder.geocode(place: snapshot) { (title, subtitle) in
                         
-                        guard self.place.snapshot == snapshot else {
+                        guard self.place == snapshot else {
                             
                             return
                         }
@@ -104,22 +107,29 @@ extension Modern.PlacemarksDemo {
         // MARK: View
         
         var body: some View {
-            Modern.PlacemarksDemo.MapView(
-                place: self.place.snapshot,
-                onTap: { coordinate in
+            
+            Group {
+                
+                if let place = self.place {
                     
-                    self.demoAsynchronousTransaction(coordinate: coordinate)
+                    Modern.PlacemarksDemo.MapView(
+                        place: place,
+                        onTap: { coordinate in
+                            
+                            self.demoAsynchronousTransaction(coordinate: coordinate)
+                        }
+                    )
+                    .overlay(
+                        InstructionsView(
+                            ("Random", "Sets random coordinate"),
+                            ("Tap", "Sets to tapped coordinate")
+                        )
+                        .padding(.leading, 10)
+                        .padding(.bottom, 40),
+                        alignment: .bottomLeading
+                    )
                 }
-            )
-            .overlay(
-                InstructionsView(
-                    ("Random", "Sets random coordinate"),
-                    ("Tap", "Sets to tapped coordinate")
-                )
-                .padding(.leading, 10)
-                .padding(.bottom, 40),
-                alignment: .bottomLeading
-            )
+            }
             .navigationBarTitle("Placemarks")
             .navigationBarItems(
                 trailing: Button("Random") {
@@ -132,7 +142,7 @@ extension Modern.PlacemarksDemo {
         
         // MARK: Private
         
-        private var sinkCancellable: AnyCancellable? = nil
+        private var sinkCancellable: AnyCancellable?
         private let geocoder = Modern.PlacemarksDemo.Geocoder()
     }
 }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PokedexDemo/Modern.PokedexDemo.MainView.swift

@@ -12,30 +12,28 @@ extension Modern.PokedexDemo {
 
     // MARK: - Modern.PokedexDemo.MainView
 
-    struct MainView: View {
+    struct MainView<ListView: View>: View {
 
         // MARK: Internal
-
-        init() {
-
-            self.pokedexEntries = Modern.PokedexDemo.pokedexEntries
+        
+        init(
+            listView: @escaping () -> ListView
+        ) {
+            
+            self.listView = listView
         }
 
 
         // MARK: View
 
         var body: some View {
-            let pokedexEntries = self.pokedexEntries.snapshot
-            return ZStack {
+            ZStack {
                 
-                Modern.PokedexDemo.ListView(
-                    service: self.service,
-                    listPublisher: self.pokedexEntries
-                )
+                self.listView()
                 .frame(minHeight: 0, maxHeight: .infinity)
                 .edgesIgnoringSafeArea(.vertical)
                 
-                if pokedexEntries.isEmpty {
+                if self.pokedexEntries.isEmpty {
                     
                     VStack(alignment: .center, spacing: 30) {
                         Text("This demo needs to make a network connection to download Pokedex entries")
@@ -64,11 +62,17 @@ extension Modern.PokedexDemo {
 
         // MARK: Private
         
-        @ObservedObject
-        private var pokedexEntries: ListPublisher<Modern.PokedexDemo.PokedexEntry>
+        @ListState(
+            From<Modern.PokedexDemo.PokedexEntry>()
+                .orderBy(.ascending(\.$index)),
+            in: Modern.PokedexDemo.dataStack
+        )
+        private var pokedexEntries
 
         @ObservedObject
         private var service: Modern.PokedexDemo.Service = .init()
+        
+        private let listView: () -> ListView
     }
 }
 
@@ -82,7 +86,9 @@ struct _Demo_Modern_PokedexDemo_MainView_Preview: PreviewProvider {
 
     static var previews: some View {
 
-        Modern.PokedexDemo.MainView()
+        Modern.PokedexDemo.MainView(
+            listView: Modern.PokedexDemo.UIKit.ListView.init
+        )
     }
 }
 

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PokedexDemo/Modern.PokedexDemo.UIKit.ItemCell.swift

@@ -7,9 +7,9 @@ import CoreStore
 import UIKit
 
 
-// MARK: - Modern.PokedexDemo
+// MARK: - Modern.PokedexDemo.UIKit
 
-extension Modern.PokedexDemo {
+extension Modern.PokedexDemo.UIKit {
 
     // MARK: - Modern.PokedexDemo.ItemCell
     
@@ -17,7 +17,7 @@ extension Modern.PokedexDemo {
         
         // MARK: Internal
         
-        static let reuseIdentifier: String = NSStringFromClass(Modern.PokedexDemo.ItemCell.self)
+        static let reuseIdentifier: String = NSStringFromClass(Modern.PokedexDemo.UIKit.ItemCell.self)
         
         func setPokedexEntry(
             _ pokedexEntry: Modern.PokedexDemo.PokedexEntry,
@@ -61,6 +61,7 @@ extension Modern.PokedexDemo {
                 
                 contentView.backgroundColor = UIColor.placeholderText.withAlphaComponent(0.1)
                 contentView.layer.cornerRadius = 10
+                contentView.layer.cornerCurve = .continuous
                 contentView.layer.masksToBounds = true
             }
             

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PokedexDemo/Modern.PokedexDemo.UIKit.ListView.swift

@@ -5,9 +5,9 @@
 import CoreStore
 import SwiftUI
 
-// MARK: - Modern.PokedexDemo
+// MARK: - Modern.PokedexDemo.UIKit
 
-extension Modern.PokedexDemo {
+extension Modern.PokedexDemo.UIKit {
     
     // MARK: - Modern.PokedexDemo.ListView
 
@@ -15,19 +15,20 @@ extension Modern.PokedexDemo {
         
         // MARK: Internal
         
-        init(
-            service: Modern.PokedexDemo.Service,
-            listPublisher: ListPublisher<Modern.PokedexDemo.PokedexEntry>
-        ) {
+        init() {
             
-            self.service = service
-            self.listPublisher = listPublisher
+            self.service = Modern.PokedexDemo.Service.init()
+            self.listPublisher = Modern.PokedexDemo.dataStack
+                .publishList(
+                    From<Modern.PokedexDemo.PokedexEntry>()
+                        .orderBy(.ascending(\.$index))
+                )
         }
         
         
         // MARK: UIViewControllerRepresentable
 
-        typealias UIViewControllerType = Modern.PokedexDemo.ListViewController
+        typealias UIViewControllerType = Modern.PokedexDemo.UIKit.ListViewController
 
         func makeUIViewController(context: Self.Context) -> UIViewControllerType {
             
@@ -53,7 +54,7 @@ extension Modern.PokedexDemo {
 
 #if DEBUG
 
-struct _Demo_Modern_PokedexDemo_ListView_Preview: PreviewProvider {
+struct _Demo_Modern_PokedexDemo_UIKit_ListView_Preview: PreviewProvider {
     
     // MARK: PreviewProvider
     
@@ -62,10 +63,7 @@ struct _Demo_Modern_PokedexDemo_ListView_Preview: PreviewProvider {
         let service = Modern.PokedexDemo.Service()
         service.fetchPokedexEntries()
         
-        return Modern.PokedexDemo.ListView(
-            service: service,
-            listPublisher: Modern.PokedexDemo.pokedexEntries
-        )
+        return Modern.PokedexDemo.UIKit.ListView()
     }
 }
 

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PokedexDemo/Modern.PokedexDemo.UIKit.ListViewController.swift

@@ -6,9 +6,9 @@ import CoreStore
 import UIKit
 
 
-// MARK: - Modern.PokedexDemo
+// MARK: - Modern.PokedexDemo.UIKit
 
-extension Modern.PokedexDemo {
+extension Modern.PokedexDemo.UIKit {
     
     // MARK: - Modern.PokedexDemo.ListViewController
     
@@ -65,8 +65,8 @@ extension Modern.PokedexDemo {
             self.collectionView.backgroundColor = UIColor.systemBackground
             
             self.collectionView.register(
-                Modern.PokedexDemo.ItemCell.self,
-                forCellWithReuseIdentifier: Modern.PokedexDemo.ItemCell.reuseIdentifier
+                Modern.PokedexDemo.UIKit.ItemCell.self,
+                forCellWithReuseIdentifier: Modern.PokedexDemo.UIKit.ItemCell.reuseIdentifier
             )
 
             self.startObservingList()
@@ -84,9 +84,9 @@ extension Modern.PokedexDemo {
             cellProvider: { (collectionView, indexPath, pokedexEntry) in
                 
                 let cell = collectionView.dequeueReusableCell(
-                    withReuseIdentifier: Modern.PokedexDemo.ItemCell.reuseIdentifier,
+                    withReuseIdentifier: Modern.PokedexDemo.UIKit.ItemCell.reuseIdentifier,
                     for: indexPath
-                ) as! Modern.PokedexDemo.ItemCell
+                ) as! Modern.PokedexDemo.UIKit.ItemCell
                 cell.setPokedexEntry(pokedexEntry, service: self.service)
                 return cell
             }

Demo/⭐️Sources/⭐️Demos/⭐️Modern/⭐️PokedexDemo/Modern.PokedexDemo.UIKit.swift

@@ -0,0 +1,13 @@
+//
+// Demo
+// Copyright © 2020 John Rommel Estropia, Inc. All rights reserved.
+
+
+// MARK: - Modern.PokedexDemo
+
+extension Modern.PokedexDemo {
+    
+    // MARK: - UIKit
+    
+    enum UIKit {}
+}

Package.swift

@@ -29,10 +29,10 @@ import PackageDescription
 let package = Package(
     name: "CoreStore",
     platforms: [
-           .macOS(.v10_12), .iOS(.v10), .tvOS(.v10), .watchOS(.v3)
+           .macOS(.v10_13), .iOS(.v11), .tvOS(.v11), .watchOS(.v4)
     ],
     products: [
-        .library(name: "CoreStore", type: .static, targets: ["CoreStore"])
+        .library(name: "CoreStore", targets: ["CoreStore"])
     ],
     dependencies: [],
     targets: [

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-<img alt="CoreStore" src="https://cloud.githubusercontent.com/assets/3029684/13373932/84daee2a-ddb8-11e5-99db-fdf415620102.png" width=614 />
+<img alt="CoreStore" src="https://github.com/JohnEstropia/CoreStore/raw/develop/CoreStore.png" width=614 />
 <br />
 <br />
 Unleashing the real power of Core Data with the elegance and safety of Swift
@@ -19,42 +19,17 @@ Unleashing the real power of Core Data with the elegance and safety of Swift
 <br />
 </p>
 
-* **Swift 5.3:** iOS 10+ / macOS 10.12+ / watchOS 3.0+ / tvOS 10.0+
-* Previously supported Swift versions: [Swift 3.2](https://github.com/JohnEstropia/CoreStore/tree/4.2.3), [Swift 4.2](https://github.com/JohnEstropia/CoreStore/tree/6.2.1), [Swift 5.0](https://github.com/JohnEstropia/CoreStore/tree/6.3.2), [Swift 5.1](https://github.com/JohnEstropia/CoreStore/tree/7.0.4)
+* **Swift 5.4:** iOS 11+ / macOS 10.13+ / watchOS 4.0+ / tvOS 11.0+
+* Previously supported Swift versions: [Swift 3.2](https://github.com/JohnEstropia/CoreStore/tree/4.2.3), [Swift 4.2](https://github.com/JohnEstropia/CoreStore/tree/6.2.1), [Swift 5.0](https://github.com/JohnEstropia/CoreStore/tree/6.3.2), [Swift 5.1](https://github.com/JohnEstropia/CoreStore/tree/7.0.4), [Swift 5.3](https://github.com/JohnEstropia/CoreStore/tree/7.3.1)
 
-Upgrading from CoreStore 6.x (swift 5.0) to 7.x (Swift 5.1)? Check out the [🆕 features](#features) and make sure to read the [Change logs](https://github.com/JohnEstropia/CoreStore/releases).
+Upgrading from previous CoreStore versions? Check out the [🆕 features](#features) and make sure to read the [Change logs](https://github.com/JohnEstropia/CoreStore/releases).
 
-CoreStore is now part of the [Swift Source Compatibility projects](https://swift.org/source-compatibility/#current-list-of-projects).
-
-
-## Why use CoreStore?
-
-CoreStore was (and is) heavily shaped by real-world needs of developing data-dependent apps. It enforces safe and convenient Core Data usage while letting you take advantage of the industry's encouraged best practices.
-
-### Features
-
-- **Backwards-portable DiffableDataSources implementation!** `UITableViews` and `UICollectionViews` now have a new ally: `ListPublisher`s provide diffable snapshots that make reloading animations very easy and very safe. Say goodbye to `UITableViews` and `UICollectionViews` reload errors!
-- **💎Tight design around Swift’s code elegance and type safety.** CoreStore fully utilizes Swift's community-driven language features.
-- **🚦Safer concurrency architecture.** CoreStore makes it hard to fall into common concurrency mistakes. The main `NSManagedObjectContext` is strictly read-only, while all updates are done through serial *transactions*. *(See [Saving and processing transactions](#saving-and-processing-transactions))*
-- **🔍Clean fetching and querying API.** Fetching objects is easy, but querying for raw aggregates (`min`, `max`, etc.) and raw property values is now just as convenient. *(See [Fetching and querying](#fetching-and-querying))*
-- **🔭Type-safe, easy to configure observers.** You don't have to deal with the burden of setting up `NSFetchedResultsController`s and KVO. As an added bonus, list and object observable types all support multiple observers. This means you can have multiple view controllers efficiently share a single resource! *(See [Observing changes and notifications](#observing-changes-and-notifications))*
-- **📥Efficient importing utilities.** Map your entities once with their corresponding import source (JSON for example), and importing from *transactions* becomes elegant. Uniquing is also done with an efficient find-and-replace algorithm. *(See [Importing data](#importing-data))*
-- **🗑Say goodbye to *.xcdatamodeld* files!** While CoreStore supports `NSManagedObject`s, it offers `CoreStoreObject` whose subclasses can declare type-safe properties all in Swift code without the need to maintain separate resource files for the models. As bonus, these special properties support custom types, and can be used to create type-safe keypaths and queries. *(See [Type-safe `CoreStoreObject`s](#type-safe-corestoreobjects))*
-- **🔗Progressive migrations.** No need to think how to migrate from all previous model versions to your latest model. Just tell the `DataStack` the sequence of version strings (`MigrationChain`s) and CoreStore will automatically use progressive migrations when needed. *(See [Migrations](#migrations))*
-- **Easier custom migrations.** Say goodbye to *.xcmappingmodel* files; CoreStore can now infer entity mappings when possible, while still allowing an easy way to write custom mappings. *(See [Migrations](#migrations))*
-- **📝Plug-in your own logging framework.** Although a default logger is built-in, all logging, asserting, and error reporting can be funneled to `CoreStoreLogger` protocol implementations. *(See [Logging and error reporting](#logging-and-error-reporting))*
-- **⛓Heavy support for multiple persistent stores per data stack.** CoreStore lets you manage separate stores in a single `DataStack`, just the way *.xcdatamodeld* configurations are designed to. CoreStore will also manage one stack by default, but you can create and manage as many as you need. *(See [Setting up](#setting-up))*
-- **🎯Free to name entities and their class names independently.** CoreStore gets around a restriction with other Core Data wrappers where the entity name should be the same as the `NSManagedObject` subclass name. CoreStore loads entity-to-class mappings from the managed object model file, so you can assign independent names for the entities and their class names.
-- **📙Full Documentation.** No magic here; all public classes, functions, properties, etc. have detailed *Apple Docs*. This *README* also introduces a lot of concepts and explains a lot of CoreStore's behavior.
-- **ℹ️Informative (and pretty) logs.** All CoreStore and Core Data-related types now have very informative and pretty print outputs! *(See [Logging and error reporting](#logging-and-error-reporting))*
-- **🎗Objective-C support!** Is your project transitioning from Objective-C to Swift but still can't quite fully convert some huge classes to Swift yet? CoreStore adjusts to the ever-increasing Swift adoption. While still written in pure Swift, all CoreStore types have their corresponding Objective-C-visible "bridging classes". *(See [Objective-C support](#objective-c-support))*
-- **🛡More extensive Unit Tests.** Extending CoreStore is safe without having to worry about breaking old behavior.
-
-*Have ideas that may benefit other Core Data users? [Feature Request](https://github.com/JohnEstropia/CoreStore/issues)s are welcome!*
+CoreStore is part of the [Swift Source Compatibility projects](https://swift.org/source-compatibility/#current-list-of-projects).
 
 ## Contents
 
 - [TL;DR (a.k.a. sample codes)](#tldr-aka-sample-codes)
+- [Why use CoreStore?](#why-use-corestore)
 - [Architecture](#architecture)
 - CoreStore Tutorials (All of these have demos in the **Demo** app project!)
     - [Setting up](#setting-up)
@@ -94,13 +69,28 @@ CoreStore was (and is) heavily shaped by real-world needs of developing data-dep
         - [Observe detailed list changes](#observe-detailed-list-changes)
     - [Objective-C support](#objective-c-support)
     - [Type-safe `CoreStoreObject`s](#type-safe-corestoreobjects)
-        - 🆕[New `@Field` Property Wrapper syntax](#new-field-property-wrapper-syntax)
-            - 🆕[`@Field.Stored` ](#fieldstored)
-            - 🆕[`@Field.Virtual` ](#fieldvirtual)
-            - 🆕[`@Field.Coded` ](#fieldcoded)
-            - 🆕[`@Field.Relationship` ](#fieldrelationship)
-            - 🆕[`@Field` usage notes](#field-usage-notes)
+        - [New `@Field` Property Wrapper syntax](#new-field-property-wrapper-syntax)
+            - [`@Field.Stored` ](#fieldstored)
+            - [`@Field.Virtual` ](#fieldvirtual)
+            - [`@Field.Coded` ](#fieldcoded)
+            - [`@Field.Relationship` ](#fieldrelationship)
+            - [`@Field` usage notes](#field-usage-notes)
         - [`VersionLock`s](#versionlocks)
+    - [Reactive Programming](#reactive-programming)
+        - [RxSwift](#rxswift)
+        - 🆕[Combine](#combine)
+            - 🆕[`DataStack.reactive`](#datastackreactive)
+            - 🆕[`ListPublisher.reactive`](#listpublisherreactive)
+            - 🆕[`ObjectPublisher.reactive`](#objectpublisherreactive)
+    - 🆕[SwiftUI Utilities](#swiftui-utilities)
+        - 🆕[SwiftUI Views`](#swiftui-views)
+            - 🆕[`ListReader`](#listreader)
+            - 🆕[`ObjectReader`](#objectreader)
+        - 🆕[SwiftUI Property Wrappers](#swiftui-property-wrappers)
+            - 🆕[`ListState`](#liststate)
+            - 🆕[`ObjectState`](#objectstate)
+        - 🆕[SwiftUI Extensions](#swiftui-extensions)
+            - 🆕[`ForEach`](#foreach)
 - [Roadmap](#roadmap)
 - [Installation](#installation)
 - [Changesets](#changesets)
@@ -112,6 +102,18 @@ CoreStore was (and is) heavily shaped by real-world needs of developing data-dep
 
 ## TL;DR (a.k.a. sample codes)
 
+Pure-Swift models:
+```swift
+class Person: CoreStoreObject {
+    @Field.Stored("name")
+    var name: String = ""
+    
+    @Field.Relationship("pets", inverse: \Dog.$master)
+    var pets: Set<Dog>
+}
+```
+(Classic `NSManagedObject`s also supported)
+
 Setting-up with progressive migration support:
 ```swift
 dataStack = DataStack(
@@ -134,7 +136,7 @@ Starting transactions:
 ```swift
 dataStack.perform(
     asynchronous: { (transaction) -> Void in
-        let person = transaction.create(Into<MyPersonEntity>())
+        let person = transaction.create(Into<Person>())
         person.name = "John Smith"
         person.age = 42
     },
@@ -149,13 +151,13 @@ dataStack.perform(
 
 Fetching objects (simple):
 ```swift
-let people = try dataStack.fetchAll(From<MyPersonEntity>())
+let people = try dataStack.fetchAll(From<Person>())
 ```
 
 Fetching objects (complex):
 ```swift
 let people = try dataStack.fetchAll(
-    From<MyPersonEntity>()
+    From<Person>()
         .where(\.age > 30),
         .orderBy(.ascending(\.name), .descending(.\age)),
         .tweak({ $0.includesPendingChanges = false })
@@ -165,7 +167,7 @@ let people = try dataStack.fetchAll(
 Querying values:
 ```swift
 let maxAge = try dataStack.queryValue(
-    From<MyPersonEntity>()
+    From<Person>()
         .select(Int.self, .maximum(\.age))
 )
 ```
@@ -175,6 +177,33 @@ But really, there's a reason I wrote this huge *README*. Read up on the details!
 Check out the **Demo** app project for sample codes as well!
 
 
+## Why use CoreStore?
+
+CoreStore was (and is) heavily shaped by real-world needs of developing data-dependent apps. It enforces safe and convenient Core Data usage while letting you take advantage of the industry's encouraged best practices.
+
+### Features
+
+- **🆕[SwiftUI](#swiftui-utilities) and [Combine](#combine) API utilities.** `ListPublisher`s and `ObjectPublisher`s now have their `@ListState` and `@ObjectState` SwiftUI property wrappers. Combine `Publisher` s are also available through the `ListPublisher.reactive`, `ObjectPublisher.reactive`, and `DataStack.reactive` namespaces.
+- **Backwards-portable [DiffableDataSources implementation](#observe-a-diffable-list)!** `UITableViews` and `UICollectionViews` now have a new ally: `ListPublisher`s provide diffable snapshots that make reloading animations very easy and very safe. Say goodbye to `UITableViews` and `UICollectionViews` reload errors!
+- **💎Tight design around Swift’s code elegance and type safety.** CoreStore fully utilizes Swift's community-driven language features.
+- **🚦Safer concurrency architecture.** CoreStore makes it hard to fall into common concurrency mistakes. The main `NSManagedObjectContext` is strictly read-only, while all updates are done through serial *transactions*. *(See [Saving and processing transactions](#saving-and-processing-transactions))*
+- **🔍Clean fetching and querying API.** Fetching objects is easy, but querying for raw aggregates (`min`, `max`, etc.) and raw property values is now just as convenient. *(See [Fetching and querying](#fetching-and-querying))*
+- **🔭Type-safe, easy to configure observers.** You don't have to deal with the burden of setting up `NSFetchedResultsController`s and KVO. As an added bonus, list and object observable types all support multiple observers. This means you can have multiple view controllers efficiently share a single resource! *(See [Observing changes and notifications](#observing-changes-and-notifications))*
+- **📥Efficient importing utilities.** Map your entities once with their corresponding import source (JSON for example), and importing from *transactions* becomes elegant. Uniquing is also done with an efficient find-and-replace algorithm. *(See [Importing data](#importing-data))*
+- **🗑Say goodbye to *.xcdatamodeld* files!** While CoreStore supports `NSManagedObject`s, it offers `CoreStoreObject` whose subclasses can declare type-safe properties all in Swift code without the need to maintain separate resource files for the models. As bonus, these special properties support custom types, and can be used to create type-safe keypaths and queries. *(See [Type-safe `CoreStoreObject`s](#type-safe-corestoreobjects))*
+- **🔗Progressive migrations.** No need to think how to migrate from all previous model versions to your latest model. Just tell the `DataStack` the sequence of version strings (`MigrationChain`s) and CoreStore will automatically use progressive migrations when needed. *(See [Migrations](#migrations))*
+- **Easier custom migrations.** Say goodbye to *.xcmappingmodel* files; CoreStore can now infer entity mappings when possible, while still allowing an easy way to write custom mappings. *(See [Migrations](#migrations))*
+- **📝Plug-in your own logging framework.** Although a default logger is built-in, all logging, asserting, and error reporting can be funneled to `CoreStoreLogger` protocol implementations. *(See [Logging and error reporting](#logging-and-error-reporting))*
+- **⛓Heavy support for multiple persistent stores per data stack.** CoreStore lets you manage separate stores in a single `DataStack`, just the way *.xcdatamodeld* configurations are designed to. CoreStore will also manage one stack by default, but you can create and manage as many as you need. *(See [Setting up](#setting-up))*
+- **🎯Free to name entities and their class names independently.** CoreStore gets around a restriction with other Core Data wrappers where the entity name should be the same as the `NSManagedObject` subclass name. CoreStore loads entity-to-class mappings from the managed object model file, so you can assign independent names for the entities and their class names.
+- **📙Full Documentation.** No magic here; all public classes, functions, properties, etc. have detailed *Apple Docs*. This *README* also introduces a lot of concepts and explains a lot of CoreStore's behavior.
+- **ℹ️Informative (and pretty) logs.** All CoreStore and Core Data-related types now have very informative and pretty print outputs! *(See [Logging and error reporting](#logging-and-error-reporting))*
+- **🎗Objective-C support!** Is your project transitioning from Objective-C to Swift but still can't quite fully convert some huge classes to Swift yet? CoreStore adjusts to the ever-increasing Swift adoption. While still written in pure Swift, all CoreStore types have their corresponding Objective-C-visible "bridging classes". *(See [Objective-C support](#objective-c-support))*
+- **🛡More extensive Unit Tests.** Extending CoreStore is safe without having to worry about breaking old behavior.
+
+*Have ideas that may benefit other Core Data users? [Feature Request](https://github.com/JohnEstropia/CoreStore/issues)s are welcome!*
+
+
 
 ## Architecture
 For maximum safety and performance, CoreStore will enforce coding patterns and practices it was designed for. (Don't worry, it's not as scary as it sounds.) But it is advisable to understand the "magic" of CoreStore before you use it in your apps.
@@ -270,6 +299,19 @@ try dataStack.addStorageAndWait(
     )
 )
 ```
+Asynchronous variant:
+```swift
+try dataStack.addStorage(
+    InMemoryStore(
+        configuration: "Config2
+    ),
+    completion: { storage in
+        // ...
+    }
+)
+```
+
+(A reactive-programming variant of this method is explained in detail in the section on [`DataStack` Combine publishers](#datastackreactive))
 
 ### Local Store
 The most common `StorageInterface` you will probably use is the `SQLiteStore`, which saves data in a local SQLite file.
@@ -291,7 +333,9 @@ CoreStore can decide the default values for these properties, so `SQLiteStore`s
 try dataStack.addStorageAndWait(SQLiteStore())
 ```
 
-The file-related properties above are actually requirements of another protocol that `SQLiteStore` implements, the `LocalStorage` protocol:
+(The asynchronous variant of this method is explained further in the next section on [Migrations](#starting-migrations), and a reactive-programming variant in the section on [`DataStack` Combine publishers](#datastackreactive))
+
+The file-related properties of `SQLiteStore` are actually requirements of another protocol that it implements, the `LocalStorage` protocol:
 ```swift
 public protocol LocalStorage: StorageInterface {
     var fileURL: NSURL { get }
@@ -462,6 +506,8 @@ let migrationProgress: Progress? = try dataStack.addStorage(
 ```
 The `completion` block reports a `SetupResult` that indicates success or failure.
 
+(A reactive-programming variant of this method is explained further in the section on [`DataStack` Combine publishers](#datastackreactive))
+
 Notice that this method also returns an optional `Progress`. If `nil`, no migrations are needed, thus progress reporting is unnecessary as well. If not `nil`, you can use this to track migration progress by using standard KVO on the `"fractionCompleted"` key, or by using a closure-based utility exposed in *Progress+Convenience.swift*:
 ```swift
 migrationProgress?.setProgressHandler { [weak self] (progress) -> Void in
@@ -1459,6 +1505,8 @@ Note that the owner instance will not be retained. You may call `ObjectPublisher
 
 The `ObjectSnapshot` returned from the `ObjectPublisher.snapshot` property returns a full-copy `struct` of all properties of the object. This is ideal for managing states as they are thread-safe and are not affected by further changes to the actual object.  `ObjectPublisher` automatically updates its `snapshot` value to the latest state of the object. 
 
+(A reactive-programming variant of this method is explained in detail in the section on [`ObjectPublisher` Combine publishers](#objectpublisherreactive))
+
 
 ### Observe a single object's per-property updates
 
@@ -1512,6 +1560,8 @@ Note that the owner instance will not be retained. You may call `ListPublisher.r
 
 The `ListSnapshot` returned from the `ListPublisher.snapshot` property returns a full-copy `struct` of all sections and `NSManagedObject` items in the list. This is ideal for managing states as they are thread-safe and are not affected by further changes to the result set.  `ListPublisher` automatically updates its `snapshot` value to the latest state of the fetch. 
 
+(A reactive-programming variant of this method is explained in detail in the section on [`ListPublisher` Combine publishers](#listpublisherreactive))
+
 Unlike  `ListMonitor`s (See [`ListMonitor` examples](#observe-detailed-list-changes) below), a `ListPublisher` does not track detailed inserts, deletes, and moves. In return, a `ListPublisher` is a lot more lightweight and are designed to work well with `DiffableDataSource.TableViewAdapter`s and `DiffableDataSource.CollectionViewAdapter`s:
 ```swift
 self.dataSource = DiffableDataSource.CollectionViewAdapter<Person>(
@@ -1814,13 +1864,13 @@ Starting CoreStore 7.1.0, `CoreStoreObject` properties may be converted to `@Fie
 The `@Field.Stored` property wrapper is used for persisted value types. This is the replacement for "non-transient" `Value.Required` and `Value.Optional` properties.
 
 <table>
-<tr><th>Before</th><th>`@Field.Stored`</th></tr>
+<tr><th>Before</th><th><pre lang=swift>@Field.Stored</pre></th></tr>
 <tr>
 <td><pre lang=swift>
 class Person: CoreStoreObject {
     <br />
-    let title = Value.Required<String>("title", initial: "Mr.")
-    let nickname = Value.Optional<String>("nickname")
+    let title = Value.Required&lt;String&gt;("title", initial: "Mr.")
+    let nickname = Value.Optional&lt;String&gt;("nickname")
 }
 </pre></td>
 <td><pre lang=swift>
@@ -1845,20 +1895,20 @@ class Person: CoreStoreObject {
 The `@Field.Virtual` property wrapper is used for unsaved, computed value types. This is the replacement for "transient" `Value.Required` and `Value.Optional` properties.
 
 <table>
-<tr><th>Before</th><th>`@Field.Virtual`</th></tr>
+<tr><th>Before</th><th><pre lang=swift>@Field.Virtual</pre></th></tr>
 <tr>
 <td><pre lang=swift>
 class Animal: CoreStoreObject {
     <br />
-    let speciesPlural = Value.Required<String>(
+    let speciesPlural = Value.Required&lt;String&gt;(
         "speciesPlural",
         transient: true,
         customGetter: Animal.getSpeciesPlural(_:)
     )
     <br />
-    let species = Value.Required<String>("species", initial: "")
+    let species = Value.Required&lt;String&gt;("species", initial: "")
     <br />
-    static func getSpeciesPlural(_ partialObject: PartialObject<Animal>) -> String? {
+    static func getSpeciesPlural(_ partialObject: PartialObject&lt;Animal&gt;) -> String? {
         let species = partialObject.value(for: { $0.species })
         return species + "s"
     }
@@ -1893,12 +1943,12 @@ The `@Field.Coded` property wrapper is used for binary-codable values. This is t
 > ‼️ The current `Transformable.Required` and `Transformable.Optional` mechanism have no safe one-to-one conversion to `@Field.Coded`. Please use `@Field.Coded` only for newly added attributes.
 
 <table>
-<tr><th>Before</th><th>`@Field.Coded`</th></tr>
+<tr><th>Before</th><th><pre lang=swift>@Field.Coded</pre></th></tr>
 <tr>
 <td><pre lang=swift>
 class Vehicle: CoreStoreObject {
     <br />
-    let color = Transformable.Optional<UIColor>("color", initial: .white)
+    let color = Transformable.Optional&lt;UIColor&gt;("color", initial: .white)
 }
 </pre></td>
 <td><pre lang=swift>
@@ -1946,16 +1996,16 @@ The type of relationship is determined by the `@Field.Relationship`  generic typ
 - `Set<T>` : To-many unordered relationship
 
 <table>
-<tr><th>Before</th><th>`@Field.Stored`</th></tr>
+<tr><th>Before</th><th><pre lang=swift>@Field.Stored</pre></th></tr>
 <tr>
 <td><pre lang=swift>
 class Pet: CoreStoreObject {
     <br />
-    let master = Relationship.ToOne<Person>("master")
+    let master = Relationship.ToOne&lt;Person&gt;("master")
 }
 class Person: CoreStoreObject {
     <br />
-    let pets: Relationship.ToManyUnordered<Pet>("pets", inverse: \.$master)
+    let pets: Relationship.ToManyUnordered&lt;Pet&gt;("pets", inverse: \.$master)
 }
 </pre></td>
 <td><pre lang=swift>
@@ -1967,7 +2017,7 @@ class Pet: CoreStoreObject {
 class Person: CoreStoreObject {
     <br />
     @Field.Relationship("pets", inverse: \.$master)
-    var pets: Set<Pet>
+    var pets: Set&lt;Pet&gt;
 }
 </pre></td>
 </tr>
@@ -2059,6 +2109,438 @@ Once the version lock is set, any changes in the properties or to the model will
 
 <img width="700" alt="VersionLock failure" src="https://cloud.githubusercontent.com/assets/3029684/26525666/92f46f0c-4399-11e7-9395-4379f6f20876.png" />
 
+## Reactive Programming
+### RxSwift
+RxSwift utilities are available through the [RxCoreStore](https://github.com/JohnEstropia/RxCoreStore) external module.
+
+### Combine
+
+Combine publishers are available from the `DataStack`, `ListPublisher`, and `ObjectPublisher`'s `.reactive` namespace property.
+
+#### `DataStack.reactive`
+
+Adding a storage through `DataStack.reactive.addStorage(_:)` returns a publisher that reports a `MigrationProgress` `enum` value. The `.migrating` value is only emitted if the storage goes through a migration. Refer to the [Setting up](#setting-up) section for details on the storage setup process itself.
+
+```swift
+dataStack.reactive
+    .addStorage(
+        SQLiteStore(fileName: "core_data.sqlite")
+    )
+    .sink(
+        receiveCompletion: { result in
+            // ...
+        },
+        receiveValue: { (progress) in
+            print("\(round(progress.fractionCompleted * 100)) %") // 0.0 ~ 1.0
+            switch progress {
+            case .migrating(let storage, let nsProgress):
+                // ...
+            case .finished(let storage, let migrationRequired):
+                // ...
+            }
+        }
+    )
+    .store(in: &cancellables)
+```
+
+[Transactions](#saving-and-processing-transactions) are also available as publishers through `DataStack.reactive.perform(_:)`, which returns a Combine `Future` that emits any type returned from the closure parameter:
+```swift
+dataStack.reactive
+    .perform(
+        asynchronous: { (transaction) -> (inserted: Set<NSManagedObject>, deleted: Set<NSManagedObject>) in
+
+            // ...
+            return (
+                transaction.insertedObjects(),
+                transaction.deletedObjects()
+            )
+        }
+    )
+    .sink(
+        receiveCompletion: { result in
+            // ...
+        },
+        receiveValue: { value in
+            let inserted = dataStack.fetchExisting(value0.inserted)
+            let deleted = dataStack.fetchExisting(value0.deleted)
+            // ...
+        }
+    )
+    .store(in: &cancellables)
+```
+
+For importing convenience, `ImportableObject` and `ImportableUniqueObjects` can be imported directly through `DataStack.reactive.import[Unique]Object(_:source:)` and `DataStack.reactive.import[Unique]Objects(_:sourceArray:)` without having to create a transaction block. In this case the publisher emits objects that are already usable directly from the main queue:
+```swift
+dataStack.reactive
+    .importUniqueObjects(
+        Into<Person>(),
+        sourceArray: [
+            ["name": "John"],
+            ["name": "Bob"],
+            ["name": "Joe"]
+        ]
+    )
+    .sink(
+        receiveCompletion: { result in
+            // ...
+        },
+        receiveValue: { (people) in
+            XCTAssertEqual(people?.count, 3)
+            // ...
+        }
+    )
+    .store(in: &cancellables)
+```
+
+#### `ListPublisher.reactive`
+
+`ListPublisher`s can be used to emit `ListSnapshot`s through Combine using `ListPublisher.reactive.snapshot(emitInitialValue:)`. The snapshot values are emitted in the main queue:
+```swift
+listPublisher.reactive
+    .snapshot(emitInitialValue: true)
+    .sink(
+        receiveCompletion: { result in
+            // ...
+        },
+        receiveValue: { (listSnapshot) in
+            dataSource.apply(
+                listSnapshot,
+                animatingDifferences: true
+            )
+        }
+    )
+    .store(in: &cancellables)
+```
+
+#### `ObjectPublisher.reactive`
+
+`ObjectPublisher`s can be used to emit `ObjectSnapshot`s through Combine using `ObjectPublisher.reactive.snapshot(emitInitialValue:)`. The snapshot values are emitted in the main queue:
+```swift
+objectPublisher.reactive
+    .snapshot(emitInitialValue: true)
+    .sink(
+        receiveCompletion: { result in
+            // ...
+        },
+        receiveValue: { (objectSnapshot) in
+            tableViewCell.setObject(objectSnapshot)
+        }
+    )
+    .store(in: &tableViewCell.cancellables)
+```
+
+
+## SwiftUI Utilities
+
+Observing list and object changes in SwiftUI can be done through a couple of approaches. One is by creating [views that autoupdates their contents](#swiftui-views), or by declaring [property wrappers that trigger view updates](#swiftui-property-wrappers). Both approaches are implemented almost the same internally, but this lets you be flexible depending on the structure of your custom `View`s.
+
+### SwiftUI Views
+
+CoreStore provides `View` containers that automatically update their contents when data changes.
+
+#### `ListReader`
+
+A `ListReader` observes changes to a `ListPublisher` and creates its content views dynamically. The builder closure receives a `ListSnapshot` value that can be used to create the contents:
+```swift
+let people: ListPublisher<Person>
+
+var body: some View {
+   List {
+       ListReader(self.people) { listSnapshot in
+           ForEach(objectIn: listSnapshot) { person in
+               // ...
+           }
+       }
+   }
+   .animation(.default)
+}
+```
+As shown above, a typical use case is to use it together with CoreStore's [`ForEach` extensions](#foreach).
+
+A `KeyPath` can also be optionally provided to extract specific properties of the `ListSnapshot`:
+```swift
+let people: ListPublisher<Person>
+
+var body: some View {
+    ListReader(self.people, keyPath: \.count) { count in
+        Text("Number of members: \(count)")
+    }
+}
+```
+
+#### `ObjectReader`
+
+An `ObjectReader` observes changes to an `ObjectPublisher` and creates its content views dynamically. The builder closure receives an `ObjectSnapshot` value that can be used to create the contents:
+```swift
+let person: ObjectPublisher<Person>
+
+var body: some View {
+   ObjectReader(self.person) { objectSnapshot in
+       // ...
+   }
+   .animation(.default)
+}
+```
+
+A `KeyPath` can also be optionally provided to extract specific properties of the `ObjectSnapshot`:
+```swift
+let person: ObjectPublisher<Person>
+
+var body: some View {
+    ObjectReader(self.person, keyPath: \.fullName) { fullName in
+        Text("Name: \(fullName)")
+    }
+}
+```
+
+By default, an `ObjectReader` does not create its views wheen the object observed is deleted from the store. In those cases, the `placeholder:` argument can be used to provide a custom `View` to display when the object is deleted:
+```swift
+let person: ObjectPublisher<Person>
+
+var body: some View {
+   ObjectReader(
+       self.person,
+       content: { objectSnapshot in
+           // ...
+       },
+       placeholder: { Text("Record not found") }
+   )
+}
+```
+
+### SwiftUI Property Wrappers
+
+As an alternative to `ListReader` and `ObjectReader`, CoreStore also provides property wrappers that trigger view updates when the data changes.
+
+#### `ListState`
+
+A `@ListState` property exposes a `ListSnapshot` value that automatically updates to the latest changes.
+```swift
+@ListState
+var people: ListSnapshot<Person>
+
+init(listPublisher: ListPublisher<Person>) {
+   self._people = .init(listPublisher)
+}
+
+var body: some View {
+   List {
+       ForEach(objectIn: self.people) { objectSnapshot in
+           // ...
+       }
+   }
+   .animation(.default)
+}
+```
+As shown above, a typical use case is to use it together with CoreStore's [`ForEach` extensions](#foreach).
+
+If a `ListPublisher` instance is not available yet, the fetch can be done inline by providing the fetch clauses and the `DataStack` instance. By doing so the property can be declared without an initial value:
+```swift
+@ListState(
+    From<Person>()
+        .sectionBy(\.age)
+        .where(\.isMember == true)
+        .orderBy(.ascending(\.lastName))
+)
+var people: ListSnapshot<Person>
+
+var body: some View {
+    List {
+        ForEach(sectionIn: self.people) { section in
+            Section(header: Text(section.sectionID)) {
+                ForEach(objectIn: section) { person in
+                    // ...
+                }
+            }
+        }
+    }
+    .animation(.default)
+}
+```
+
+For other initialization variants, refer to the *ListState.swift*  source documentations.
+
+
+#### `ObjectState`
+
+An `@ObjectState` property exposes an optional `ObjectSnapshot` value that automatically updates to the latest changes.
+```swift
+@ObjectState
+var person: ObjectSnapshot<Person>?
+
+init(objectPublisher: ObjectPublisher<Person>) {
+   self._person = .init(objectPublisher)
+}
+
+var body: some View {
+   HStack {
+       if let person = self.person {
+           AsyncImage(person.$avatarURL)
+           Text(person.$fullName)
+       }
+       else {
+           Text("Record removed")
+       }
+   }
+}
+```
+As shown above, the property's value will be `nil` if the object has been deleted, so this can be used to display placeholders if needed.
+
+### SwiftUI Extensions
+
+For convenience, CoreStore provides extensions to the standard SwiftUI types.
+
+#### `ForEach`
+
+Several `ForEach` initializer overloads are available. Choose depending on your input data and the expected closure data. Refer to the table below (Take note of the argument labels as they are important):
+
+<table>
+<tr><th>Data</th><th>Example</th></tr>
+<tr>
+<td>
+Signature: 
+<pre lang=swift>
+ForEach(_: [ObjectSnapshot&lt;O&gt;])
+</pre>
+Closure: 
+<pre lang=swift>
+ObjectSnapshot&lt;O&gt;
+</pre>
+</td>
+<td><pre lang=swift>
+let array: [ObjectSnapshot&lt;Person&gt;]
+<br />
+var body: some View {
+    <br />
+    List {
+        <br />
+        ForEach(self.array) { objectSnapshot in
+            <br />
+            // ...
+        }
+    }
+}
+</pre></td>
+</tr>
+<tr>
+<td>
+Signature: 
+<pre lang=swift>
+ForEach(objectIn: ListSnapshot&lt;O&gt;)
+</pre>
+Closure: 
+<pre lang=swift>
+ObjectPublisher&lt;O&gt;
+</pre>
+</td>
+<td><pre lang=swift>
+let listSnapshot: ListSnapshot&lt;Person&gt;
+<br />
+var body: some View {
+    <br />
+    List {
+        <br />
+        ForEach(objectIn: self.listSnapshot) { objectPublisher in
+            <br />
+            // ...
+        }
+    }
+}
+</pre></td>
+</tr>
+<tr>
+<td>
+Signature: 
+<pre lang=swift>
+ForEach(objectIn: [ObjectSnapshot&lt;O&gt;])
+</pre>
+Closure: 
+<pre lang=swift>
+ObjectPublisher&lt;O&gt;
+</pre>
+</td>
+<td><pre lang=swift>
+let array: [ObjectSnapshot&lt;Person&gt;]
+<br />
+var body: some View {
+    <br />
+    List {
+        <br />
+        ForEach(objectIn: self.array) { objectPublisher in
+            <br />
+            // ...
+        }
+    }
+}
+</pre></td>
+</tr>
+<tr>
+<td>
+Signature: 
+<pre lang=swift>
+ForEach(sectionIn: ListSnapshot&lt;O&gt;)
+</pre>
+Closure: 
+<pre lang=swift>
+[ListSnapshot&lt;O&gt;.SectionInfo]
+</pre>
+</td>
+<td><pre lang=swift>
+let listSnapshot: ListSnapshot&lt;Person&gt;
+<br />
+var body: some View {
+    <br />
+    List {
+        <br />
+        ForEach(sectionIn: self.listSnapshot) { sectionInfo in
+            <br />
+            // ...
+        }
+    }
+}
+</pre></td>
+</tr>
+<tr>
+<td>
+Signature: 
+<pre lang=swift>
+ForEach(objectIn: ListSnapshot&lt;O&gt;.SectionInfo)
+</pre>
+Closure: 
+<pre lang=swift>
+ObjectPublisher&lt;O&gt;
+</pre>
+</td>
+<td><pre lang=swift>
+let listSnapshot: ListSnapshot&lt;Person&gt;
+<br />
+var body: some View {
+    <br />
+    List {
+        <br />
+        ForEach(sectionIn: self.listSnapshot) { sectionInfo in
+            <br />
+            ForEach(objectIn: sectionInfo) { objectPublisher in
+               <br />
+                // ...
+            }
+        }
+    }
+}
+</pre></td>
+</tr>
+</table>
+
+
+# Roadmap
+
+### Prototyping stage
+- [ ] Widget/Extensions storage-sharing support
+- [ ] CloudKit support
+
+### Under consideration
+- [ ] Derived attributes
+- [ ] Cross-storage relationships (via Fetched Attributes)
 
 # Installation
 - Requires:
@@ -2073,7 +2555,7 @@ Once the version lock is set, any changes in the properties or to the model will
 ### Install with CocoaPods
 In your `Podfile`, add
 ```
-pod 'CoreStore', '~> 7.2'
+pod 'CoreStore', '~> 8.0'
 ```
 and run 
 ```
@@ -2084,7 +2566,7 @@ This installs CoreStore as a framework. Declare `import CoreStore` in your swift
 ### Install with Carthage
 In your `Cartfile`, add
 ```
-github "JohnEstropia/CoreStore" >= 7.3.0
+github "JohnEstropia/CoreStore" >= 8.0.0
 ```
 and run 
 ```
@@ -2095,7 +2577,7 @@ This installs CoreStore as a framework. Declare `import CoreStore` in your swift
 #### Install with Swift Package Manager:
 ```swift
 dependencies: [
-    .package(url: "https://github.com/JohnEstropia/CoreStore.git", from: "7.3.1"))
+    .package(url: "https://github.com/JohnEstropia/CoreStore.git", from: "8.0.1"))
 ]
 ```
 Declare `import CoreStore` in your swift file to use the library.

Sources/AsynchronousDataTransaction.swift

@@ -158,9 +158,19 @@ public final class AsynchronousDataTransaction: BaseDataTransaction {
     
     // MARK: Internal
     
-    internal init(mainContext: NSManagedObjectContext, queue: DispatchQueue) {
+    internal init(
+        mainContext: NSManagedObjectContext,
+        queue: DispatchQueue,
+        sourceIdentifier: Any?
+    ) {
         
-        super.init(mainContext: mainContext, queue: queue, supportsUndo: false, bypassesQueueing: false)
+        super.init(
+            mainContext: mainContext,
+            queue: queue,
+            supportsUndo: false,
+            bypassesQueueing: false,
+            sourceIdentifier: sourceIdentifier
+        )
     }
     
     internal func autoCommit(_ completion: @escaping (_ hasChanges: Bool, _ error: CoreStoreError?) -> Void) {
@@ -168,12 +178,15 @@ public final class AsynchronousDataTransaction: BaseDataTransaction {
         self.isCommitted = true
         let group = DispatchGroup()
         group.enter()
-        self.context.saveAsynchronouslyWithCompletion { (hasChanges, error) -> Void in
-            
-            completion(hasChanges, error)
-            self.result = (hasChanges, error)
-            group.leave()
-        }
+        self.context.saveAsynchronously(
+            sourceIdentifier: self.sourceIdentifier,
+            completion: { (hasChanges, error) -> Void in
+                
+                completion(hasChanges, error)
+                self.result = (hasChanges, error)
+                group.leave()
+            }
+        )
         group.wait()
         self.context.reset()
     }

Sources/BaseDataTransaction.swift

@@ -412,6 +412,11 @@ public /*abstract*/ class BaseDataTransaction {
     
     // MARK: 3rd Party Utilities
     
+    /**
+     An arbitrary value that identifies the source of this transaction. Callers of the transaction can provide this value through the `DataStack.perform(...)` methods.
+     */
+    public let sourceIdentifier: Any?
+    
     /**
      Allow external libraries to store custom data in the transaction. App code should rarely have a need for this.
      ```
@@ -435,7 +440,13 @@ public /*abstract*/ class BaseDataTransaction {
     internal var isCommitted = false
     internal var result: (hasChanges: Bool, error: CoreStoreError?)?
     
-    internal init(mainContext: NSManagedObjectContext, queue: DispatchQueue, supportsUndo: Bool, bypassesQueueing: Bool) {
+    internal init(
+        mainContext: NSManagedObjectContext,
+        queue: DispatchQueue,
+        supportsUndo: Bool,
+        bypassesQueueing: Bool,
+        sourceIdentifier: Any?
+    ) {
         
         let context = mainContext.temporaryContextInTransactionWithConcurrencyType(
             queue == .main
@@ -446,6 +457,7 @@ public /*abstract*/ class BaseDataTransaction {
         self.context = context
         self.supportsUndo = supportsUndo
         self.bypassesQueueing = bypassesQueueing
+        self.sourceIdentifier = sourceIdentifier
         
         context.parentTransaction = self
         context.isTransactionContext = true

Sources/CSCoreStore+Migrating.swift

@@ -1,107 +0,0 @@
-//
-//  CSCoreStore+Migrating.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CSCoreStore
-
-@available(*, deprecated, message: "Call methods directly from the CSDataStack instead")
-extension CSCoreStore {
-    
-    /**
-     Asynchronously adds a `CSInMemoryStore` to the `defaultStack`. Migrations are also initiated by default.
-     ```
-     NSError *error;
-     NSProgress *migrationProgress = [dataStack
-         addInMemoryStorage:[CSInMemoryStore new]
-         completion:^(CSSetupResult *result) {
-             if (result.isSuccess) {
-                 // ...
-             }
-         }
-         error: &error];
-     ```
-     - parameter storage: the `CSInMemoryStore` instance
-     - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `CSSetupResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a failure `CSSetupResult` result if an error occurs asynchronously.
-     */
-    public static func addInMemoryStorage(_ storage: CSInMemoryStore, completion: @escaping (CSSetupResult) -> Void) {
-        
-        self.defaultStack.addInMemoryStorage(storage, completion: completion)
-    }
-    
-    /**
-     Asynchronously adds a `CSSQLiteStore` to the `defaultStack`. Migrations are also initiated by default.
-     ```
-     NSError *error;
-     NSProgress *migrationProgress = [dataStack
-         addInMemoryStorage:[[CSSQLiteStore alloc]
-         initWithFileName:@"core_data.sqlite"
-         configuration:@"Config1"]
-         completion:^(CSSetupResult *result) {
-             if (result.isSuccess) {
-                 // ...
-             }
-         }
-         error: &error];
-     ```
-     - parameter storage: the `CSSQLiteStore` instance
-     - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `CSSetupResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a failure `CSSetupResult` result if an error occurs asynchronously. Note that the `CSLocalStorage` associated to the `-[CSSetupResult storage]` may not always be the same instance as the parameter argument if a previous `CSLocalStorage` was already added at the same URL and with the same configuration.
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: an `NSProgress` instance if a migration has started. `nil` if no migrations are required or if `error` was set.
-     */
-    public static func addSQLiteStorage(_ storage: CSSQLiteStore, completion: @escaping (CSSetupResult) -> Void, error: NSErrorPointer) -> Progress? {
-        
-        return self.defaultStack.addSQLiteStorage(storage, completion: completion, error: error)
-    }
-    
-    /**
-     Migrates a `CSSQLiteStore` to match the `defaultStack`'s managed object model version. This method does NOT add the migrated store to the data stack.
-     
-     - parameter storage: the `CSSQLiteStore` instance
-     - parameter completion: the closure to be executed on the main queue when the migration completes, either due to success or failure. The closure's `CSMigrationResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a failure `CSSetupResult` result if an error occurs asynchronously.
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: an `NSProgress` instance if a migration has started. `nil` if no migrations are required or if `error` was set.
-     */
-    @objc
-    public static func upgradeStorageIfNeeded(_ storage: CSSQLiteStore, completion: @escaping (CSMigrationResult) -> Void, error: NSErrorPointer) -> Progress? {
-        
-        return self.defaultStack.upgradeStorageIfNeeded(storage, completion: completion, error: error)
-    }
-    
-    /**
-     Checks the migration steps required for the `CSSQLiteStore` to match the `defaultStack`'s managed object model version.
-     
-     - parameter storage: the `CSSQLiteStore` instance
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: a `CSMigrationType` array indicating the migration steps required for the store, or an empty array if the file does not exist yet. Otherwise, `nil` is returned and the `error` argument is set if either inspection of the store failed, or if no mapping model was found/inferred.
-     */
-    @objc
-    public static func requiredMigrationsForSQLiteStore(_ storage: CSSQLiteStore, error: NSErrorPointer) -> [CSMigrationType]? {
-        
-        return self.defaultStack.requiredMigrationsForSQLiteStore(storage, error: error)
-    }
-}

Sources/CSCoreStore+Observing.swift

@@ -1,114 +0,0 @@
-//
-//  CSCoreStore+Observing.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CSCoreStore
-
-@available(*, deprecated, message: "Call methods directly from the CSDataStack instead")
-@available(macOS 10.12, *)
-extension CSCoreStore {
-    
-    /**
-     Using the `defaultStack`, creates an `CSObjectMonitor` for the specified `NSManagedObject`. Multiple `CSObjectObserver`s may then register themselves to be notified when changes are made to the `NSManagedObject`.
-     
-     - parameter object: the `NSManagedObject` to observe changes from
-     - returns: a `CSObjectMonitor` that monitors changes to `object`
-     */
-    @objc
-    public static func monitorObject(_ object: NSManagedObject) -> CSObjectMonitor {
-        
-        return self.defaultStack.monitorObject(object)
-    }
-    
-    /**
-     Using the `defaultStack`, creates a `CSListMonitor` for a list of `NSManagedObject`s that satisfy the specified fetch clauses. Multiple `CSListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for fetching the object list. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: a `CSListMonitor` instance that monitors changes to the list
-     */
-    @objc
-    public static func monitorListFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> CSListMonitor {
-        
-        return self.defaultStack.monitorListFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, asynchronously creates a `CSListMonitor` for a list of `NSManagedObject`s that satisfy the specified fetch clauses. Multiple `CSListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `CSListMonitor` instance
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for fetching the object list. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     */
-    @objc
-    public static func monitorListByCreatingAsynchronously(_ createAsynchronously: @escaping (CSListMonitor) -> Void, from: CSFrom, fetchClauses: [CSFetchClause])  {
-        
-        return self.defaultStack.monitorListByCreatingAsynchronously(
-            createAsynchronously,
-            from: from,
-            fetchClauses: fetchClauses
-        )
-    }
-    
-    /**
-     Using the `defaultStack`, creates a `CSListMonitor` for a sectioned list of `NSManagedObject`s that satisfy the specified fetch clauses. Multiple `CSListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter sectionBy: a `CSSectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `CSFetchClause` instances for fetching the object list. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: a `CSListMonitor` instance that monitors changes to the list
-     */
-    @objc
-    public static func monitorSectionedListFrom(_ from: CSFrom, sectionBy: CSSectionBy, fetchClauses: [CSFetchClause]) -> CSListMonitor {
-        
-        return self.defaultStack.monitorSectionedListFrom(
-            from,
-            sectionBy: sectionBy,
-            fetchClauses: fetchClauses
-        )
-    }
-    
-    /**
-     Using the `defaultStack`, asynchronously creates a `CSListMonitor` for a sectioned list of `NSManagedObject`s that satisfy the specified fetch clauses. Multiple `CSListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `CSListMonitor` instance
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter sectionBy: a `CSSectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `CSFetchClause` instances for fetching the object list. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     */
-    @objc
-    public static func monitorSectionedListByCreatingAsynchronously(_ createAsynchronously: @escaping (CSListMonitor) -> Void, from: CSFrom, sectionBy: CSSectionBy, fetchClauses: [CSFetchClause]) {
-        
-        self.defaultStack.monitorSectionedListByCreatingAsynchronously(
-            createAsynchronously,
-            from: from,
-            sectionBy: sectionBy,
-            fetchClauses: fetchClauses
-        )
-    }
-}

Sources/CSCoreStore+Querying.swift

@@ -1,179 +0,0 @@
-//
-//  CSCoreStore+Querying.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CSCoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-extension CSCoreStore {
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObject` instance in the transaction's context from a reference created from a transaction or from a different managed object context.
-     
-     - parameter object: a reference to the object created/fetched outside the transaction
-     - returns: the `NSManagedObject` instance if the object exists in the transaction, or `nil` if not found.
-     */
-    @objc
-    public static func fetchExistingObject(_ object: NSManagedObject) -> Any? {
-        
-        return self.defaultStack.fetchExistingObject(object)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObject` instance in the transaction's context from an `NSManagedObjectID`.
-     
-     - parameter objectID: the `NSManagedObjectID` for the object
-     - returns: the `NSManagedObject` instance if the object exists in the transaction, or `nil` if not found.
-     */
-    @objc
-    public static func fetchExistingObjectWithID(_ objectID: NSManagedObjectID) -> Any? {
-        
-        return self.defaultStack.fetchExistingObjectWithID(objectID)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObject` instances in the transaction's context from references created from a transaction or from a different managed object context.
-     
-     - parameter objects: an array of `NSManagedObject`s created/fetched outside the transaction
-     - returns: the `NSManagedObject` array for objects that exists in the transaction
-     */
-    @objc
-    public static func fetchExistingObjects(_ objects: [NSManagedObject]) -> [Any] {
-        
-        return self.defaultStack.fetchExistingObjects(objects)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObject` instances in the transaction's context from a list of `NSManagedObjectID`.
-     
-     - parameter objectIDs: the `NSManagedObjectID` array for the objects
-     - returns: the `NSManagedObject` array for objects that exists in the transaction
-     */
-    @objc
-    public static func fetchExistingObjectsWithIDs(_ objectIDs: [NSManagedObjectID]) -> [Any] {
-        
-        return self.defaultStack.fetchExistingObjectsWithIDs(objectIDs)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the first `NSManagedObject` instance that satisfies the specified `CSFetchClause`s. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for the fetch request. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: the first `NSManagedObject` instance that satisfies the specified `CSFetchClause`s
-     */
-    @objc
-    public static func fetchOneFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> Any? {
-        
-        return self.defaultStack.fetchOneFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches all `NSManagedObject` instances that satisfy the specified `CSFetchClause`s. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for the fetch request. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: all `NSManagedObject` instances that satisfy the specified `CSFetchClause`s
-     */
-    @objc
-    public static func fetchAllFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> [Any]? {
-        
-        return self.defaultStack.fetchAllFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the number of `NSManagedObject`s that satisfy the specified `CSFetchClause`s. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for the fetch request. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: the number `NSManagedObject`s that satisfy the specified `CSFetchClause`s
-     */
-    @objc
-    public static func fetchCountFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> NSNumber? {
-        
-        return self.defaultStack.fetchCountFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObjectID` for the first `NSManagedObject` that satisfies the specified `CSFetchClause`s. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `CSFetchClause` instances for the fetch request. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `NSManagedObject` that satisfies the specified `CSFetchClause`s
-     */
-    @objc
-    public static func fetchObjectIDFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> NSManagedObjectID? {
-        
-        return self.defaultStack.fetchObjectIDFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, fetches the `NSManagedObjectID` for all `NSManagedObject`s that satisfy the specified `CSFetchClause`s. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `CSWhere`, `CSOrderBy`, and `CSTweak` clauses.
-     - returns: the `NSManagedObjectID` for all `NSManagedObject`s that satisfy the specified `CSFetchClause`s
-     */
-    @objc
-    public static func fetchObjectIDsFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> [NSManagedObjectID]? {
-        
-        return self.defaultStack.fetchObjectIDsFrom(from, fetchClauses: fetchClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, queries aggregate values as specified by the `CSQueryClause`s. Requires at least a `CSSelect` clause, and optional `CSWhere`, `CSOrderBy`, `CSGroupBy`, and `CSTweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter selectClause: a `CSSelect` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `CSQueryClause` instances for the query request. Accepts `CSWhere`, `CSOrderBy`, `CSGroupBy`, and `CSTweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `CSSelect` parameter.
-     */
-    @objc
-    public static func queryValueFrom(_ from: CSFrom, selectClause: CSSelect, queryClauses: [CSQueryClause]) -> Any? {
-        
-        return self.defaultStack.queryValueFrom(from, selectClause: selectClause, queryClauses: queryClauses)
-    }
-    
-    /**
-     Using the `defaultStack`, queries a dictionary of attribute values as specified by the `CSQueryClause`s. Requires at least a `CSSelect` clause, and optional `CSWhere`, `CSOrderBy`, `CSGroupBy`, and `CSTweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `CSFrom` clause indicating the entity type
-     - parameter selectClause: a `CSSelect` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `CSQueryClause` instances for the query request. Accepts `CSWhere`, `CSOrderBy`, `CSGroupBy`, and `CSTweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `CSSelect` parameter.
-     */
-    @objc
-    public static func queryAttributesFrom(_ from: CSFrom, selectClause: CSSelect, queryClauses: [CSQueryClause]) -> [[String: Any]]? {
-        
-        return self.defaultStack.queryAttributesFrom(from, selectClause: selectClause, queryClauses: queryClauses)
-    }
-}

Sources/CSCoreStore+Setup.swift

@@ -1,129 +0,0 @@
-//
-//  CSCoreStore+Setup.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CSCoreStore
-
-@available(*, deprecated, message: "Call methods directly from the CSDataStack instead")
-extension CSCoreStore {
-    
-    /**
-     Returns the `defaultStack`'s model version. The version string is the same as the name of the version-specific .xcdatamodeld file.
-     */
-    @objc
-    public static var modelVersion: String {
-        
-        return self.defaultStack.modelVersion
-    }
-    
-    /**
-     Returns the entity name-to-class type mapping from the `defaultStack`'s model.
-     */
-    @objc
-    public static func entityTypesByNameForType(_ type: NSManagedObject.Type) -> [EntityName: NSManagedObject.Type] {
-        
-        return self.defaultStack.bridgeToSwift.entityTypesByName(for: type)
-    }
-    
-    /**
-     Returns the `NSEntityDescription` for the specified `NSManagedObject` subclass from `defaultStack`'s model.
-     */
-    @objc
-    public static func entityDescriptionForClass(_ type: NSManagedObject.Type) -> NSEntityDescription? {
-        
-        return self.defaultStack.bridgeToSwift.entityDescription(for: type)
-    }
-    
-    /**
-     Creates an `CSInMemoryStore` with default parameters and adds it to the `defaultStack`. This method blocks until completion.
-     ```
-     CSSQLiteStore *storage = [CSCoreStore addInMemoryStorageAndWaitAndReturnError:&error];
-     ```
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: the `CSInMemoryStore` added to the `defaultStack`
-     */
-    @objc
-    @discardableResult
-    public static func addInMemoryStorageAndWaitAndReturnError(_ error: NSErrorPointer) -> CSInMemoryStore? {
-        
-        return self.defaultStack.addInMemoryStorageAndWaitAndReturnError(error)
-    }
-    
-    /**
-     Creates an `CSSQLiteStore` with default parameters and adds it to the `defaultStack`. This method blocks until completion.
-     ```
-     CSSQLiteStore *storage = [CSCoreStore addSQLiteStorageAndWaitAndReturnError:&error];
-     ```
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: the `CSSQLiteStore` added to the `defaultStack`
-     */
-    @objc
-    @discardableResult
-    public static func addSQLiteStorageAndWaitAndReturnError(_ error: NSErrorPointer) -> CSSQLiteStore? {
-        
-        return self.defaultStack.addSQLiteStorageAndWaitAndReturnError(error)
-    }
-    
-    /**
-     Adds a `CSInMemoryStore` to the `defaultStack` and blocks until completion.
-     ```
-     NSError *error;
-     CSInMemoryStore *storage = [CSCoreStore
-         addStorageAndWait: [[CSInMemoryStore alloc] initWithConfiguration: @"Config1"]
-         error: &error];
-     ```
-     - parameter storage: the `CSInMemoryStore`
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: the `CSInMemoryStore` added to the `defaultStack`
-     */
-    @objc
-    @discardableResult
-    public static func addInMemoryStorageAndWait(_ storage: CSInMemoryStore, error: NSErrorPointer) -> CSInMemoryStore? {
-        
-        return self.defaultStack.addInMemoryStorageAndWait(storage, error: error)
-    }
-    
-    /**
-     Adds a `CSSQLiteStore` to the `defaultStack` and blocks until completion.
-     ```
-     NSError *error;
-     CSSQLiteStore *storage = [CSCoreStore
-         addStorageAndWait: [[CSSQLiteStore alloc] initWithConfiguration: @"Config1"]
-         error: &error];
-     ```
-     - parameter storage: the `CSSQLiteStore`
-     - parameter error: the `NSError` pointer that indicates the reason in case of an failure
-     - returns: the `CSSQLiteStore` added to the `defaultStack`
-     */
-    @objc
-    @discardableResult
-    public static func addSQLiteStorageAndWait(_ storage: CSSQLiteStore, error: NSErrorPointer) -> CSSQLiteStore? {
-        
-        return self.defaultStack.addSQLiteStorageAndWait(storage, error: error)
-    }
-}

Sources/CSCoreStore+Transaction.swift

@@ -1,95 +0,0 @@
-//
-//  CSCoreStore+Transaction.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-
-
-// MARK: - CSCoreStore
-
-@available(*, deprecated, message: "Call methods directly from the CSDataStack instead")
-extension CSCoreStore {
-    
-    /**
-     Using the `defaultStack`, begins a transaction asynchronously where `NSManagedObject` creates, updates, and deletes can be made.
-     
-     - parameter closure: the block where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
-     */
-    @objc
-    public static func beginAsynchronous(_ closure: @escaping (_ transaction: CSAsynchronousDataTransaction) -> Void) {
-        
-        self.defaultStack.beginAsynchronous(closure)
-    }
-    
-    /**
-     Using the `defaultStack`, begins a transaction synchronously where `NSManagedObject` creates, updates, and deletes can be made.
-     
-     - parameter closure: the block where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
-     - returns: `YES` if the commit succeeded, `NO` if the commit failed. If `NO`, the `error` argument will hold error information.
-     */
-    @objc
-    public static func beginSynchronous(_ closure: @escaping (_ transaction: CSSynchronousDataTransaction) -> Void, error: NSErrorPointer) -> Bool {
-        
-        return self.defaultStack.beginSynchronous(closure, error: error)
-    }
-    
-    /**
-     Using the `defaultStack`, begins a child transaction where `NSManagedObject` creates, updates, and deletes can be made. This is useful for making temporary changes, such as partially filled forms.
-     
-     To support "undo" methods such as `-undo`, `-redo`, and `-rollback`, use the `-beginSafeWithSupportsUndo:` method passing `YES` to the argument. Without "undo" support, calling those methods will raise an exception.
-     - returns: a `CSUnsafeDataTransaction` instance where creates, updates, and deletes can be made.
-     */
-    @objc
-    public static func beginUnsafe() -> CSUnsafeDataTransaction {
-        
-        return bridge {
-            
-            self.defaultStack.bridgeToSwift.beginUnsafe()
-        }
-    }
-    
-    /**
-     Using the `defaultStack`, begins a child transaction where `NSManagedObject` creates, updates, and deletes can be made. This is useful for making temporary changes, such as partially filled forms.
-     
-     - prameter supportsUndo: `-undo`, `-redo`, and `-rollback` methods are only available when this parameter is `YES`, otherwise those method will raise an exception. Note that turning on Undo support may heavily impact performance especially on iOS or watchOS where memory is limited.
-     - returns: a `CSUnsafeDataTransaction` instance where creates, updates, and deletes can be made.
-     */
-    @objc
-    public static func beginUnsafeWithSupportsUndo(_ supportsUndo: Bool) -> CSUnsafeDataTransaction {
-        
-        return bridge {
-            
-            self.defaultStack.bridgeToSwift.beginUnsafe(supportsUndo: supportsUndo)
-        }
-    }
-    
-    /**
-     Refreshes all registered objects `NSManagedObject`s in the `defaultStack`.
-     */
-    @objc
-    public static func refreshAndMergeAllObjects() {
-        
-        self.defaultStack.refreshAndMergeAllObjects()
-    }
-}

Sources/CSDataStack+Observing.swift

@@ -30,7 +30,6 @@ import CoreData
 // MARK: - CSDataStack
 
 @available(*, deprecated, message: "CoreStore Objective-C API will be removed soon.")
-@available(macOS 10.12, *)
 extension CSDataStack {
     
     /**

Sources/CSListMonitor.swift

@@ -34,7 +34,6 @@ import CoreData
  
  - SeeAlso: `ListMonitor`
  */
-@available(macOS 10.12, *)
 @objc
 public final class CSListMonitor: NSObject {
     
@@ -546,7 +545,6 @@ public final class CSListMonitor: NSObject {
 
 // MARK: - ListMonitor
 
-@available(macOS 10.12, *)
 extension ListMonitor where ListMonitor.ObjectType: NSManagedObject {
     
     // MARK: CoreStoreSwiftType

Sources/CSListObserver.swift

@@ -40,7 +40,6 @@ import CoreData
  
  - SeeAlso: `ListObserver`
  */
-@available(macOS 10.12, *)
 @objc
 public protocol CSListObserver: AnyObject {
     
@@ -91,7 +90,6 @@ public protocol CSListObserver: AnyObject {
  
  - SeeAlso: `ListObjectObserver`
  */
-@available(macOS 10.12, *)
 @objc
 public protocol CSListObjectObserver: CSListObserver {
     
@@ -152,7 +150,6 @@ public protocol CSListObjectObserver: CSListObserver {
  
  - SeeAlso: `ListSectionObserver`
  */
-@available(macOS 10.12, *)
 @objc
 public protocol CSListSectionObserver: CSListObjectObserver {
     

Sources/CSObjectMonitor.swift

@@ -34,7 +34,6 @@ import CoreData
  
  - SeeAlso: `ObjectMonitor`
  */
-@available(macOS 10.12, *)
 @objc
 public final class CSObjectMonitor: NSObject {
     
@@ -139,7 +138,6 @@ public final class CSObjectMonitor: NSObject {
 
 // MARK: - ObjectMonitor
 
-@available(macOS 10.12, *)
 extension ObjectMonitor where ObjectMonitor.ObjectType: NSManagedObject {
     
     // MARK: CoreStoreSwiftType

Sources/CSObjectObserver.swift

@@ -38,7 +38,6 @@ import CoreData
  
  - SeeAlso: `ObjectObserver`
  */
-@available(macOS 10.12, *)
 @objc
 public protocol CSObjectObserver: AnyObject {
     

Sources/CSSectionBy.swift

@@ -34,7 +34,6 @@ import CoreData
  
  - SeeAlso: `SectionBy`
  */
-@available(macOS 10.12, *)
 @objc
 public final class CSSectionBy: NSObject {
     
@@ -51,16 +50,21 @@ public final class CSSectionBy: NSObject {
     }
     
     /**
-     Initializes a `CSSectionBy` clause with the key path to use to group `CSListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Initializes a `CSSectionBy` clause with the key path to use to group `CSListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - parameter sectionKeyPath: the key path to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `CSSectionBy` clause with the key path to use to group `CSListMonitor` objects into sections
      */
     @objc
     public static func keyPath(_ sectionKeyPath: KeyPathString, sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> CSSectionBy {
         
-        return self.init(SectionBy<NSManagedObject>(sectionKeyPath, sectionIndexTransformer))
+        return self.init(
+            SectionBy<NSManagedObject>(
+                sectionKeyPath,
+                sectionIndexTransformer: sectionIndexTransformer
+            )
+        )
     }
     
     
@@ -86,7 +90,6 @@ public final class CSSectionBy: NSObject {
 
 // MARK: - SectionBy
 
-@available(macOS 10.12, *)
 extension SectionBy {
     
     // MARK: CoreStoreSwiftType
@@ -101,6 +104,9 @@ extension SectionBy {
     
     fileprivate func downcast() -> SectionBy<NSManagedObject> {
         
-        return SectionBy<NSManagedObject>(self.sectionKeyPath, self.sectionIndexTransformer)
+        return SectionBy<NSManagedObject>(
+            self.sectionKeyPath,
+            sectionIndexTransformer: self.sectionIndexTransformer
+        )
     }
 }

Sources/CSSynchronousDataTransaction.swift

@@ -49,7 +49,10 @@ public final class CSSynchronousDataTransaction: CSBaseDataTransaction, CoreStor
         
         return bridge(error) {
             
-            if case (_, let error?) = self.bridgeToSwift.context.saveSynchronously(waitForMerge: true) {
+            if case (_, let error?) = self.bridgeToSwift.context.saveSynchronously(
+                waitForMerge: true,
+                sourceIdentifier: nil
+            ) {
                 
                 throw error
             }

Sources/CSUnsafeDataTransaction.swift

@@ -46,21 +46,24 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction, CoreStoreObje
     @objc
     public func commitWithSuccess(_ success: (() -> Void)?, _ failure: ((CSError) -> Void)?) {
         
-        self.bridgeToSwift.context.saveAsynchronouslyWithCompletion { (_, error) in
-            
-            defer {
-                
-                withExtendedLifetime(self, {})
+        self.bridgeToSwift.context.saveAsynchronously(
+            sourceIdentifier: nil,
+            completion: { (_, error) in
+
+                defer {
+
+                    withExtendedLifetime(self, {})
+                }
+                if let error = error {
+
+                    failure?(error.bridgeToObjectiveC)
+                }
+                else {
+
+                    success?()
+                }
             }
-            if let error = error {
-                
-                failure?(error.bridgeToObjectiveC)
-            }
-            else {
-                
-                success?()
-            }
-        }
+        )
     }
     
     /**
@@ -71,10 +74,13 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction, CoreStoreObje
      */
     @objc
     public func commitAndWait(error: NSErrorPointer) -> Bool {
-        
+
         return bridge(error) {
             
-            if case (_, let error?) = self.bridgeToSwift.context.saveSynchronously(waitForMerge: true) {
+            if case (_, let error?) = self.bridgeToSwift.context.saveSynchronously(
+                waitForMerge: true,
+                sourceIdentifier: nil
+            ) {
                 
                 throw error
             }

Sources/CoreDataNativeType.swift

@@ -33,7 +33,7 @@ import CoreData
  Objective-C Foundation types that are natively supported by Core Data managed attributes all conform to `CoreDataNativeType`.
  */
 @objc
-public protocol CoreDataNativeType: AnyObject, NSObjectProtocol {}
+public protocol CoreDataNativeType: NSObjectProtocol {}
 
 
 // MARK: - NSNumber

Sources/CoreStore+CustomDebugStringConvertible.swift

@@ -359,7 +359,6 @@ extension UnsafeDataModelSchema: CustomDebugStringConvertible, CoreStoreDebugStr
 
 // MARK: - ListMonitor
 
-@available(macOS 10.12, *)
 fileprivate struct CoreStoreFetchedSectionInfoWrapper: CoreStoreDebugStringConvertible {
     
     // MARK: CustomDebugStringConvertible
@@ -404,7 +403,6 @@ fileprivate struct CoreStoreFetchedSectionInfoWrapper: CoreStoreDebugStringConve
     private let numberOfObjects: Int
 }
 
-@available(macOS 10.12, *)
 extension ListMonitor: CustomDebugStringConvertible, CoreStoreDebugStringConvertible {
     
     // MARK: CustomDebugStringConvertible
@@ -431,7 +429,6 @@ extension ListMonitor: CustomDebugStringConvertible, CoreStoreDebugStringConvert
 
 // MARK: - ListPublisher
 
-@available(macOS 10.12, *)
 extension ListPublisher: CustomDebugStringConvertible, CoreStoreDebugStringConvertible {
 
     // MARK: CustomDebugStringConvertible
@@ -614,7 +611,6 @@ extension MigrationType: CoreStoreDebugStringConvertible {
 
 // MARK: - ObjectMonitor
 
-@available(macOS 10.12, *)
 extension ObjectMonitor: CustomDebugStringConvertible, CoreStoreDebugStringConvertible {
     
     // MARK: CustomDebugStringConvertible
@@ -738,7 +734,6 @@ extension PartialObject: CustomDebugStringConvertible, CoreStoreDebugStringConve
 
 // MARK: - SectionBy
 
-@available(macOS 10.12, *)
 extension SectionBy: CustomDebugStringConvertible, CoreStoreDebugStringConvertible {
     
     // MARK: CustomDebugStringConvertible
@@ -1259,33 +1254,20 @@ extension NSEntityDescription: CoreStoreDebugStringConvertible {
     
     public var coreStoreDumpString: String {
         
-        var info: DumpInfo = [
+        return createFormattedString(
+            "(", ")",
             ("managedObjectClassName", self.managedObjectClassName!),
             ("name", self.name as Any),
+            ("indexes", self.indexes),
             ("isAbstract", self.isAbstract),
             ("superentity?.name", self.superentity?.name as Any),
             ("subentities", self.subentities.map({ $0.name })),
             ("properties", self.properties),
+            ("uniquenessConstraints", self.uniquenessConstraints),
             ("userInfo", self.userInfo as Any),
             ("versionHash", self.versionHash),
             ("versionHashModifier", self.versionHashModifier as Any),
             ("renamingIdentifier", self.renamingIdentifier as Any)
-        ]
-        if #available(iOS 11.0, macOS 10.13, watchOS 4.0, tvOS 11.0, *) {
-            
-            info.append(("indexes", self.indexes))
-        }
-        else {
-            
-            info.append(("compoundIndexes", self.compoundIndexes))
-        }
-        if #available(macOS 10.11, iOS 9.0, *) {
-            
-            info.append(("uniquenessConstraints", self.uniquenessConstraints))
-        }
-        return createFormattedString(
-            "(", ")",
-            info
         )
     }
 }

Sources/CoreStore+Migration.swift

@@ -1,102 +0,0 @@
-//
-//  CoreStore+Migration.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-extension CoreStore {
-
-    /**
-     Asynchronously adds a `StorageInterface` to the `CoreStoreDefaults.dataStack`. Migrations are also initiated by default.
-     ```
-     dataStack.addStorage(
-         InMemoryStore(configuration: "Config1"),
-         completion: { result in
-             switch result {
-             case .success(let storage): // ...
-             case .failure(let error): // ...
-             }
-         }
-     )
-     ```
-     - parameter storage: the storage
-     - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `SetupResult` argument indicates the result. Note that the `StorageInterface` associated to the `SetupResult.success` may not always be the same instance as the parameter argument if a previous `StorageInterface` was already added at the same URL and with the same configuration.
-     */
-    public static func addStorage<T>(_ storage: T, completion: @escaping (SetupResult<T>) -> Void) {
-        
-        CoreStoreDefaults.dataStack.addStorage(storage, completion: completion)
-    }
-
-    /**
-     Asynchronously adds a `LocalStorage` to the `CoreStoreDefaults.dataStack`. Migrations are also initiated by default.
-     ```
-     let migrationProgress = dataStack.addStorage(
-         SQLiteStore(fileName: "core_data.sqlite", configuration: "Config1"),
-         completion: { result in
-             switch result {
-             case .success(let storage): // ...
-             case .failure(let error): // ...
-             }
-         }
-     )
-     ```
-     - parameter storage: the local storage
-     - parameter completion: the closure to be executed on the main queue when the process completes, either due to success or failure. The closure's `SetupResult` argument indicates the result. Note that the `LocalStorage` associated to the `SetupResult.success` may not always be the same instance as the parameter argument if a previous `LocalStorage` was already added at the same URL and with the same configuration.
-     - returns: a `Progress` instance if a migration has started, or `nil` if either no migrations are required or if a failure occured.
-     */
-    public static func addStorage<T: LocalStorage>(_ storage: T, completion: @escaping (SetupResult<T>) -> Void) -> Progress? {
-        
-        return CoreStoreDefaults.dataStack.addStorage(storage, completion: completion)
-    }
-
-    /**
-     Migrates a local storage to match the `CoreStoreDefaults.dataStack`'s managed object model version. This method does NOT add the migrated store to the data stack.
-
-     - parameter storage: the local storage
-     - parameter completion: the closure to be executed on the main queue when the migration completes, either due to success or failure. The closure's `MigrationResult` argument indicates the result. This closure is NOT executed if an error is thrown, but will be executed with a `.failure` result if an error occurs asynchronously.
-     - throws: a `CoreStoreError` value indicating the failure
-     - returns: a `Progress` instance if a migration has started, or `nil` is no migrations are required
-     */
-    public static func upgradeStorageIfNeeded<T: LocalStorage>(_ storage: T, completion: @escaping (MigrationResult) -> Void) throws -> Progress? {
-        
-        return try CoreStoreDefaults.dataStack.upgradeStorageIfNeeded(storage, completion: completion)
-    }
-    
-    /**
-     Checks the migration steps required for the storage to match the `CoreStoreDefaults.dataStack`'s managed object model version.
-     
-     - parameter storage: the local storage
-     - throws: a `CoreStoreError` value indicating the failure
-     - returns: a `MigrationType` array indicating the migration steps required for the store, or an empty array if the file does not exist yet. Otherwise, an error is thrown if either inspection of the store failed, or if no mapping model was found/inferred.
-     */
-    public static func requiredMigrationsForStorage<T: LocalStorage>(_ storage: T) throws -> [MigrationType] {
-        
-        return try CoreStoreDefaults.dataStack.requiredMigrationsForStorage(storage)
-    }
-}

Sources/CoreStore+Observing.swift

@@ -1,236 +0,0 @@
-//
-//  CoreStore+Observing.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-@available(macOS 10.12, *)
-extension CoreStore {
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, creates an `ObjectMonitor` for the specified `DynamicObject`. Multiple `ObjectObserver`s may then register themselves to be notified when changes are made to the `DynamicObject`.
-     
-     - parameter object: the `DynamicObject` to observe changes from
-     - returns: an `ObjectMonitor` that monitors changes to `object`
-     */
-    public static func monitorObject<O: DynamicObject>(_ object: O) -> ObjectMonitor<O> {
-        
-        return CoreStoreDefaults.dataStack.monitorObject(object)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: a `ListMonitor` instance that monitors changes to the list
-     */
-    public static func monitorList<O>(_ from: From<O>, _ fetchClauses: FetchClause...) -> ListMonitor<O> {
-        
-        return CoreStoreDefaults.dataStack.monitorList(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: a `ListMonitor` instance that monitors changes to the list
-     */
-    public static func monitorList<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) -> ListMonitor<O> {
-        
-        return CoreStoreDefaults.dataStack.monitorList(from, fetchClauses)
-    }
-    
-    /**
-     Creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let monitor = dataStack.monitorList(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
-     */
-    public static func monitorList<B: FetchChainableBuilderType>(_ clauseChain: B) -> ListMonitor<B.ObjectType> {
-        
-        return CoreStoreDefaults.dataStack.monitorList(clauseChain.from, clauseChain.fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, asynchronously creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     */
-    public static func monitorList<O>(createAsynchronously: @escaping (ListMonitor<O>) -> Void, _ from: From<O>, _ fetchClauses: FetchClause...) {
-        
-        CoreStoreDefaults.dataStack.monitorList(createAsynchronously: createAsynchronously, from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, asynchronously creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     */
-    public static func monitorList<O>(createAsynchronously: @escaping (ListMonitor<O>) -> Void, _ from: From<O>, _ fetchClauses: [FetchClause])  {
-        
-        CoreStoreDefaults.dataStack.monitorList(createAsynchronously: createAsynchronously, from, fetchClauses)
-    }
-    
-    /**
-     Asynchronously creates a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     ```
-     dataStack.monitorList(
-         createAsynchronously: { (monitor) in
-             self.monitor = monitor
-         },
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     */
-    public static func monitorList<B: FetchChainableBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
-        
-        CoreStoreDefaults.dataStack.monitorList(
-            createAsynchronously: createAsynchronously,
-            clauseChain.from,
-            clauseChain.fetchClauses
-        )
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter sectionBy: a `SectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: a `ListMonitor` instance that monitors changes to the list
-     */
-    public static func monitorSectionedList<O>(_ from: From<O>, _ sectionBy: SectionBy<O>, _ fetchClauses: FetchClause...) -> ListMonitor<O> {
-        
-        return CoreStoreDefaults.dataStack.monitorSectionedList(from, sectionBy, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter sectionBy: a `SectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: a `ListMonitor` instance that monitors changes to the list
-     */
-    public static func monitorSectionedList<O>(_ from: From<O>, _ sectionBy: SectionBy<O>, _ fetchClauses: [FetchClause]) -> ListMonitor<O> {
-        
-        return CoreStoreDefaults.dataStack.monitorSectionedList(from, sectionBy, fetchClauses)
-    }
-    
-    /**
-     Creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType` built from a chain of clauses.
-     ```
-     let monitor = dataStack.monitorSectionedList(
-         From<MyPersonEntity>()
-             .sectionBy(\.age, { "\($0!) years old" })
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     - returns: a `ListMonitor` for a list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType`
-     */
-    public static func monitorSectionedList<B: SectionMonitorBuilderType>(_ clauseChain: B) -> ListMonitor<B.ObjectType> {
-        
-        return CoreStoreDefaults.dataStack.monitorSectionedList(
-            clauseChain.from,
-            clauseChain.sectionBy,
-            clauseChain.fetchClauses
-        )
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, asynchronously creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter from: a `From` clause indicating the entity type
-     - parameter sectionBy: a `SectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     */
-    public static func monitorSectionedList<O>(createAsynchronously: @escaping (ListMonitor<O>) -> Void, _ from: From<O>, _ sectionBy: SectionBy<O>, _ fetchClauses: FetchClause...) {
-        
-        CoreStoreDefaults.dataStack.monitorSectionedList(createAsynchronously: createAsynchronously, from, sectionBy, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, asynchronously creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified fetch clauses. Multiple `ListObserver`s may then register themselves to be notified when changes are made to the list. Since `NSFetchedResultsController` greedily locks the persistent store on initial fetch, you may prefer this method instead of the synchronous counterpart to avoid deadlocks while background updates/saves are being executed.
-     
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter from: a `From` clause indicating the entity type
-     - parameter sectionBy: a `SectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
-     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     */
-    public static func monitorSectionedList<O>(createAsynchronously: @escaping (ListMonitor<O>) -> Void, _ from: From<O>, _ sectionBy: SectionBy<O>, _ fetchClauses: [FetchClause]) {
-        
-        CoreStoreDefaults.dataStack.monitorSectionedList(createAsynchronously: createAsynchronously, from, sectionBy, fetchClauses)
-    }
-    
-    /**
-     Asynchronously creates a `ListMonitor` for a sectioned list of `DynamicObject`s that satisfy the specified `SectionMonitorBuilderType` built from a chain of clauses.
-     ```
-     dataStack.monitorSectionedList(
-         createAsynchronously: { (monitor) in
-             self.monitor = monitor
-         },
-         From<MyPersonEntity>()
-             .sectionBy(\.age, { "\($0!) years old" })
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter createAsynchronously: the closure that receives the created `ListMonitor` instance
-     - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     */
-    public static func monitorSectionedList<B: SectionMonitorBuilderType>(createAsynchronously: @escaping (ListMonitor<B.ObjectType>) -> Void, _ clauseChain: B) {
-        
-        CoreStoreDefaults.dataStack.monitorSectionedList(
-            createAsynchronously: createAsynchronously,
-            clauseChain.from,
-            clauseChain.sectionBy,
-            clauseChain.fetchClauses
-        )
-    }
-}

Sources/CoreStore+Querying.swift

@@ -1,411 +0,0 @@
-//
-//  CoreStore+Querying.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-extension CoreStore {
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `DynamicObject` instance in the `DataStack`'s context from a reference created from a transaction or from a different managed object context.
-     
-     - parameter object: a reference to the object created/fetched outside the `DataStack`
-     - returns: the `DynamicObject` instance if the object exists in the `DataStack`, or `nil` if not found.
-     */
-    public static func fetchExisting<O: DynamicObject>(_ object: O) -> O? {
-        
-        return CoreStoreDefaults.dataStack.fetchExisting(object)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `DynamicObject` instance in the `DataStack`'s context from an `NSManagedObjectID`.
-     
-     - parameter objectID: the `NSManagedObjectID` for the object
-     - returns: the `DynamicObject` instance if the object exists in the `DataStack`, or `nil` if not found.
-     */
-    public static func fetchExisting<O: DynamicObject>(_ objectID: NSManagedObjectID) -> O? {
-        
-        return CoreStoreDefaults.dataStack.fetchExisting(objectID)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `DynamicObject` instances in the `DataStack`'s context from references created from a transaction or from a different managed object context.
-     
-     - parameter objects: an array of `DynamicObject`s created/fetched outside the `DataStack`
-     - returns: the `DynamicObject` array for objects that exists in the `DataStack`
-     */
-    public static func fetchExisting<O: DynamicObject, S: Sequence>(_ objects: S) -> [O] where S.Iterator.Element == O {
-        
-        return CoreStoreDefaults.dataStack.fetchExisting(objects)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `DynamicObject` instances in the `DataStack`'s context from a list of `NSManagedObjectID`.
-     
-     - parameter objectIDs: the `NSManagedObjectID` array for the objects
-     - returns: the `DynamicObject` array for objects that exists in the `DataStack`
-     */
-    public static func fetchExisting<O: DynamicObject, S: Sequence>(_ objectIDs: S) -> [O] where S.Iterator.Element == NSManagedObjectID {
-        
-        return CoreStoreDefaults.dataStack.fetchExisting(objectIDs)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the first `DynamicObject` instance that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchOne<O>(_ from: From<O>, _ fetchClauses: FetchClause...) throws -> O? {
-        
-        return try CoreStoreDefaults.dataStack.fetchOne(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the first `DynamicObject` instance that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchOne<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) throws -> O? {
-        
-        return try CoreStoreDefaults.dataStack.fetchOne(from, fetchClauses)
-    }
-    
-    /**
-     Fetches the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let youngestTeen = dataStack.fetchOne(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
-        
-        return try CoreStoreDefaults.dataStack.fetchOne(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches all `DynamicObject` instances that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchAll<O>(_ from: From<O>, _ fetchClauses: FetchClause...) throws -> [O] {
-        
-        return try CoreStoreDefaults.dataStack.fetchAll(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches all `DynamicObject` instances that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchAll<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) throws -> [O] {
-        
-        return try CoreStoreDefaults.dataStack.fetchAll(from, fetchClauses)
-    }
-    
-    /**
-     Fetches all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let people = dataStack.fetchAll(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
-        
-        return try CoreStoreDefaults.dataStack.fetchAll(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the number of `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchCount<O>(_ from: From<O>, _ fetchClauses: FetchClause...) throws -> Int {
-        
-        return try CoreStoreDefaults.dataStack.fetchCount(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the number of `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchCount<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) throws -> Int {
-        
-        return try CoreStoreDefaults.dataStack.fetchCount(from, fetchClauses)
-    }
-    
-    /**
-     Fetches the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let numberOfAdults = dataStack.fetchCount(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
-        
-        return try CoreStoreDefaults.dataStack.fetchCount(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectID<O>(_ from: From<O>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectID(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectID<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectID(from, fetchClauses)
-    }
-    
-    /**
-     Fetches the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let youngestTeenID = dataStack.fetchObjectID(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectID(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectIDs<O>(_ from: From<O>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectIDs(from, fetchClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectIDs<O>(_ from: From<O>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectIDs(from, fetchClauses)
-    }
-    
-    /**
-     Fetches the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let idsOfAdults = transaction.fetchObjectIDs(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
-        
-        return try CoreStoreDefaults.dataStack.fetchObjectIDs(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, queries aggregate values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryValue<O, U: QueryableAttributeType>(_ from: From<O>, _ selectClause: Select<O, U>, _ queryClauses: QueryClause...) throws -> U? {
-        
-        return try CoreStoreDefaults.dataStack.queryValue(from, selectClause, queryClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, queries aggregate values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryValue<O, U: QueryableAttributeType>(_ from: From<O>, _ selectClause: Select<O, U>, _ queryClauses: [QueryClause]) throws -> U? {
-        
-        return try CoreStoreDefaults.dataStack.queryValue(from, selectClause, queryClauses)
-    }
-    
-    /**
-     Queries a property value or aggregate as specified by the `QueryChainableBuilderType` built from a chain of clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     ```
-     let averageAdultAge = dataStack.queryValue(
-         From<MyPersonEntity>()
-             .select(Int.self, .average(\.age))
-             .where(\.age > 18)
-     )
-     ```
-     - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`, or `nil` if no match was found.
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
-        
-        return try CoreStoreDefaults.dataStack.queryValue(clauseChain)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, queries a dictionary of attribute values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryAttributes<O>(_ from: From<O>, _ selectClause: Select<O, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
-        
-        return try CoreStoreDefaults.dataStack.queryAttributes(from, selectClause, queryClauses)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, queries a dictionary of attribute values as specified by the `QueryClause`s. Requires at least a `Select` clause, and optional `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     
-     - parameter from: a `From` clause indicating the entity type
-     - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
-     - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryAttributes<O>(_ from: From<O>, _ selectClause: Select<O, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
-        
-        return try CoreStoreDefaults.dataStack.queryAttributes(from, selectClause, queryClauses)
-    }
-    
-    /**
-     Queries a dictionary of attribute values or  as specified by the `QueryChainableBuilderType` built from a chain of clauses.
-     
-     A "query" differs from a "fetch" in that it only retrieves values already stored in the persistent store. As such, values from unsaved transactions or contexts will not be incorporated in the query result.
-     ```
-     let results = dataStack.queryAttributes(
-         From<MyPersonEntity>()
-             .select(
-                 NSDictionary.self,
-                 .attribute(\.age, as: "age"),
-                 .count(\.age, as: "numberOfPeople")
-             )
-             .groupBy(\.age)
-     )
-     for dictionary in results! {
-         let age = dictionary["age"] as! Int
-         let count = dictionary["numberOfPeople"] as! Int
-         print("There are \(count) people who are \(age) years old."
-     }
-     ```
-     - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`
-     - throws: `CoreStoreError.persistentStoreNotFound` if the specified entity could not be found in any store's schema.
-     */
-    public static func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
-        
-        return try CoreStoreDefaults.dataStack.queryAttributes(clauseChain)
-    }
-}

Sources/CoreStore+Setup.swift

@@ -1,117 +0,0 @@
-//
-//  CoreStore+Setup.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-import CoreData
-
-
-// MARK: - CoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-extension CoreStore {
-    
-    /**
-     Returns the `CoreStoreDefaults.dataStack`'s model version. The version string is the same as the name of a version-specific .xcdatamodeld file or `CoreStoreSchema`.
-     */
-    public static var modelVersion: String {
-        
-        return CoreStoreDefaults.dataStack.modelVersion
-    }
-    
-    /**
-     Returns the entity name-to-class type mapping from the `CoreStoreDefaults.dataStack`'s model.
-     */
-    public static func entityTypesByName(for type: NSManagedObject.Type) -> [EntityName: NSManagedObject.Type] {
-        
-        return CoreStoreDefaults.dataStack.entityTypesByName(for: type)
-    }
-    
-    /**
-     Returns the entity name-to-class type mapping from the `CoreStoreDefaults.dataStack`'s model.
-     */
-    public static func entityTypesByName(for type: CoreStoreObject.Type) -> [EntityName: CoreStoreObject.Type] {
-        
-        return CoreStoreDefaults.dataStack.entityTypesByName(for: type)
-    }
-    
-    /**
-     Returns the `NSEntityDescription` for the specified `NSManagedObject` subclass from `CoreStoreDefaults.dataStack`'s model.
-     */
-    public static func entityDescription(for type: NSManagedObject.Type) -> NSEntityDescription? {
-        
-        return CoreStoreDefaults.dataStack.entityDescription(for: type)
-    }
-    
-    /**
-     Returns the `NSEntityDescription` for the specified `CoreStoreObject` subclass from `CoreStoreDefaults.dataStack`'s model.
-     */
-    public static func entityDescription(for type: CoreStoreObject.Type) -> NSEntityDescription? {
-        
-        return CoreStoreDefaults.dataStack.entityDescription(for: type)
-    }
-    
-    /**
-     Creates an `SQLiteStore` with default parameters and adds it to the `CoreStoreDefaults.dataStack`. This method blocks until completion.
-     ```
-     try CoreStore.addStorageAndWait()
-     ```
-     - returns: the local SQLite storage added to the `CoreStoreDefaults.dataStack`
-     */
-    @discardableResult
-    public static func addStorageAndWait() throws -> SQLiteStore {
-        
-        return try CoreStoreDefaults.dataStack.addStorageAndWait(SQLiteStore())
-    }
-    
-    /**
-     Adds a `StorageInterface` to the `CoreStoreDefaults.dataStack` and blocks until completion.
-     ```
-     try CoreStore.addStorageAndWait(InMemoryStore(configuration: "Config1"))
-     ```
-     - parameter storage: the `StorageInterface`
-     - throws: a `CoreStoreError` value indicating the failure
-     - returns: the `StorageInterface` added to the `CoreStoreDefaults.dataStack`
-     */
-    @discardableResult
-    public static func addStorageAndWait<T: StorageInterface>(_ storage: T) throws -> T {
-        
-        return try CoreStoreDefaults.dataStack.addStorageAndWait(storage)
-    }
-    
-    /**
-     Adds a `LocalStorage` to the `CoreStoreDefaults.dataStack` and blocks until completion.
-     ```
-     try CoreStore.addStorageAndWait(SQLiteStore(configuration: "Config1"))
-     ```
-     - parameter storage: the local storage
-     - throws: a `CoreStoreError` value indicating the failure
-     - returns: the local storage added to the `CoreStoreDefaults.dataStack`. Note that this may not always be the same instance as the parameter argument if a previous `LocalStorage` was already added at the same URL and with the same configuration.
-     */
-    @discardableResult
-    public static func addStorageAndWait<T: LocalStorage>(_ storage: T) throws -> T {
-        
-        return try CoreStoreDefaults.dataStack.addStorageAndWait(storage)
-    }
-}

Sources/CoreStore+Transaction.swift

@@ -1,88 +0,0 @@
-//
-//  CoreStore+Transaction.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import Foundation
-
-
-// MARK: - CoreStore
-
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-extension CoreStore {
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, performs a transaction asynchronously where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. On success, the value returned from closure will be the wrapped as `.success(T)` in the `completion`'s `Result<T>`. Any errors thrown from inside the `task` will be reported as `.failure(CoreStoreError)`. To cancel/rollback changes, call `try transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
-     
-     - parameter task: the asynchronous closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
-     - parameter completion: the closure executed after the save completes. The `Result` argument of the closure will either wrap the return value of `task`, or any uncaught errors thrown from within `task`. Cancelled `task`s will be indicated by `.failure(error: CoreStoreError.userCancelled)`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
-     */
-    public static func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, completion: @escaping (AsynchronousDataTransaction.Result<T>) -> Void) {
-        
-        CoreStoreDefaults.dataStack.perform(asynchronous: task, completion: completion)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, performs a transaction asynchronously where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. On success, the value returned from closure will be the argument of the `success` closure. Any errors thrown from inside the `task` will be wrapped in a `CoreStoreError` and reported in the `failure` closure. To cancel/rollback changes, call `try transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
-     
-     - parameter task: the asynchronous closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
-     - parameter success: the closure executed after the save succeeds. The `T` argument of the closure will be the value returned from `task`.
-     - parameter failure: the closure executed if the save fails or if any errors are thrown within `task`. Cancelled `task`s will be indicated by `CoreStoreError.userCancelled`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
-     */
-    public static func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, success: @escaping (T) -> Void, failure: @escaping (CoreStoreError) -> Void) {
-        
-        CoreStoreDefaults.dataStack.perform(asynchronous: task, success: success, failure: failure)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, performs a transaction synchronously where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. On success, the value returned from closure will be the return value of `perform(synchronous:)`. Any errors thrown from inside the `task` will be thrown from `perform(synchronous:)`. To cancel/rollback changes, call `try transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
-     
-     - parameter task: the synchronous non-escaping closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
-     - parameter waitForAllObservers: When `true`, this method waits for all observers to be notified of the changes before returning. This results in more predictable data update order, but may risk triggering deadlocks. When `false`, this method does not wait for observers to be notified of the changes before returning. This results in lower risk for deadlocks, but the updated data may not have been propagated to the `DataStack` after returning. Defaults to `true`.
-     - throws: a `CoreStoreError` value indicating the failure. Cancelled `task`s will be indicated by `CoreStoreError.userCancelled`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
-     - returns: the value returned from `task`
-     */
-    public static func perform<T>(synchronous task: ((_ transaction: SynchronousDataTransaction) throws -> T), waitForAllObservers: Bool = true) throws -> T {
-        
-        return try CoreStoreDefaults.dataStack.perform(synchronous: task, waitForAllObservers: waitForAllObservers)
-    }
-    
-    /**
-     Using the `CoreStoreDefaults.dataStack`, begins a non-contiguous transaction where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. This is useful for making temporary changes, such as partially filled forms.
-     
-     - prameter supportsUndo: `undo()`, `redo()`, and `rollback()` methods are only available when this parameter is `true`, otherwise those method will raise an exception. Defaults to `false`. Note that turning on Undo support may heavily impact performance especially on iOS or watchOS where memory is limited.
-     - returns: a `UnsafeDataTransaction` instance where creates, updates, and deletes can be made.
-     */
-    public static func beginUnsafe(supportsUndo: Bool = false) -> UnsafeDataTransaction {
-        
-        return CoreStoreDefaults.dataStack.beginUnsafe(supportsUndo: supportsUndo)
-    }
-    
-    /**
-     Refreshes all registered objects `NSManagedObject`s or `CoreStoreObject`s in the `CoreStoreDefaults.dataStack`.
-     */
-    public static func refreshAndMergeAllObjects() {
-        
-        CoreStoreDefaults.dataStack.refreshAndMergeAllObjects()
-    }
-}

Sources/CoreStore.swift

@@ -1,50 +0,0 @@
-//
-//  CoreStore.swift
-//  CoreStore
-//
-//  Copyright © 2018 John Rommel Estropia
-//
-//  Permission is hereby granted, free of charge, to any person obtaining a copy
-//  of this software and associated documentation files (the "Software"), to deal
-//  in the Software without restriction, including without limitation the rights
-//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-//  copies of the Software, and to permit persons to whom the Software is
-//  furnished to do so, subject to the following conditions:
-//
-//  The above copyright notice and this permission notice shall be included in all
-//  copies or substantial portions of the Software.
-//
-//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-//  SOFTWARE.
-//
-
-import CoreData
-
-
-// MARK: - CoreStore
-
-/**
- `CoreStore` is the main entry point for all other APIs.
- */
-@available(*, deprecated, message: "Call methods directly from the DataStack instead")
-public enum CoreStore {
-
-    @available(*, unavailable, renamed: "CoreStoreDefaults.logger")
-    public static var logger: CoreStoreLogger {
-
-        get { return CoreStoreDefaults.logger }
-        set { CoreStoreDefaults.logger = newValue }
-    }
-
-    @available(*, unavailable, renamed: "CoreStoreDefaults.dataStack")
-    public static var defaultStack: DataStack {
-        
-        get { return CoreStoreDefaults.dataStack }
-        set { CoreStoreDefaults.dataStack = newValue }
-    }
-}

Sources/CoreStoreSchema.swift

@@ -564,18 +564,14 @@ public final class CoreStoreSchema: DynamicSchema {
             )
         }
         for (entity, entityDescription) in entityDescriptionsByEntity {
+            
+            if entity.uniqueConstraints.contains(where: { !$0.isEmpty }) {
 
-            if #available(macOS 10.11, iOS 9.0, *) {
-                
-                let uniqueConstraints = entity.uniqueConstraints.filter({ !$0.isEmpty })
-                if !uniqueConstraints.isEmpty {
-
-                    Internals.assert(
-                        entityDescription.superentity == nil,
-                        "Uniqueness constraints must be defined at the highest level possible."
-                    )
-                    entityDescription.uniquenessConstraints = entity.uniqueConstraints.map { $0.map { $0 as NSString } }
-                }
+                Internals.assert(
+                    entityDescription.superentity == nil,
+                    "Uniqueness constraints must be defined at the highest level possible."
+                )
+                entityDescription.uniquenessConstraints = entity.uniqueConstraints.map { $0.map { $0 as NSString } }
             }
             guard !entity.indexes.isEmpty else {
                 
@@ -586,31 +582,18 @@ public final class CoreStoreSchema: DynamicSchema {
                 entityDescription.coreStoreEntity = entity // reserialize
             }
             let attributesByName = entityDescription.attributesByName
-            if #available(iOS 11.0, macOS 10.13, watchOS 4.0, tvOS 11.0, *) {
+            entityDescription.indexes = entity.indexes.map { (compoundIndexes) in
                 
-                entityDescription.indexes = entity.indexes.map { (compoundIndexes) in
-                    
-                    return NSFetchIndexDescription.init(
-                        name: "_CoreStoreSchema_indexes_\(entityDescription.name!)_\(compoundIndexes.joined(separator: "-"))",
-                        elements: compoundIndexes.map { (keyPath) in
-                            
-                            return NSFetchIndexElementDescription(
-                                property: attributesByName[keyPath]!,
-                                collationType: .binary
-                            )
-                        }
-                    )
-                }
-            }
-            else {
-                
-                entityDescription.compoundIndexes = entity.indexes.map { (compoundIndexes) in
-                    
-                    return compoundIndexes.map { (keyPath) in
+                return NSFetchIndexDescription.init(
+                    name: "_CoreStoreSchema_indexes_\(entityDescription.name!)_\(compoundIndexes.joined(separator: "_"))",
+                    elements: compoundIndexes.map { (keyPath) in
                         
-                        return attributesByName[keyPath]!
+                        return NSFetchIndexElementDescription(
+                            property: attributesByName[keyPath]!,
+                            collationType: .binary
+                        )
                     }
-                }
+                )
             }
         }
     }

Sources/DataStack+DataSources.swift

@@ -56,6 +56,60 @@ extension DataStack {
         return context.objectPublisher(objectID: objectID)
     }
     
+    /**
+     Creates a `ListPublisher` that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
+     ```
+     let listPublisher = dataStack.listPublisher(
+         From<MyPersonEntity>()
+             .where(\.age > 18)
+             .orderBy(.ascending(\.age))
+     )
+     ```
+     Multiple objects may then register themselves to be notified when changes are made to the fetched results.
+     ```
+     listPublisher.addObserver(self) { (listPublisher) in
+         // handle changes
+     }
+     ```
+     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
+     - returns: a `ListPublisher` that broadcasts changes to the fetched results
+     */
+    public func publishList<B: FetchChainableBuilderType>(_ clauseChain: B) -> ListPublisher<B.ObjectType> {
+
+        return self.publishList(
+            clauseChain.from,
+            clauseChain.fetchClauses
+        )
+    }
+    
+    /**
+     Creates a `ListPublisher` for a sectioned list that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
+     ```
+     let listPublisher = dataStack.listPublisher(
+         From<MyPersonEntity>()
+             .sectionBy(\.age, { "\($0!) years old" })
+             .where(\.age > 18)
+             .orderBy(.ascending(\.age))
+     )
+     ```
+     Multiple objects may then register themselves to be notified when changes are made to the fetched results.
+     ```
+     listPublisher.addObserver(self) { (listPublisher) in
+         // handle changes
+     }
+     ```
+     - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
+     - returns: a `ListPublisher` that broadcasts changes to the fetched results
+     */
+    public func publishList<B: SectionMonitorBuilderType>(_ clauseChain: B) -> ListPublisher<B.ObjectType> {
+
+        return self.publishList(
+            clauseChain.from,
+            clauseChain.sectionBy,
+            clauseChain.fetchClauses
+        )
+    }
+    
     /**
      Creates a `ListPublisher` for the specified `From` and `FetchClause`s. Multiple objects may then register themselves to be notified when changes are made to the fetched results.
      
@@ -93,32 +147,6 @@ extension DataStack {
         )
     }
     
-    /**
-     Creates a `ListPublisher` that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let listPublisher = dataStack.listPublisher(
-         From<MyPersonEntity>()
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     Multiple objects may then register themselves to be notified when changes are made to the fetched results.
-     ```
-     listPublisher.addObserver(self) { (listPublisher) in
-         // handle changes
-     }
-     ```
-     - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: a `ListPublisher` that broadcasts changes to the fetched results
-     */
-    public func publishList<B: FetchChainableBuilderType>(_ clauseChain: B) -> ListPublisher<B.ObjectType> {
-
-        return self.publishList(
-            clauseChain.from,
-            clauseChain.fetchClauses
-        )
-    }
-    
     /**
      Creates a `ListPublisher` for a sectioned list that satisfy the fetch clauses. Multiple objects may then register themselves to be notified when changes are made to the fetched results.
      
@@ -161,37 +189,9 @@ extension DataStack {
             }
         )
     }
-    
-    /**
-     Creates a `ListPublisher` for a sectioned list that satisfy the specified `FetchChainableBuilderType` built from a chain of clauses.
-     ```
-     let listPublisher = dataStack.listPublisher(
-         From<MyPersonEntity>()
-             .sectionBy(\.age, { "\($0!) years old" })
-             .where(\.age > 18)
-             .orderBy(.ascending(\.age))
-     )
-     ```
-     Multiple objects may then register themselves to be notified when changes are made to the fetched results.
-     ```
-     listPublisher.addObserver(self) { (listPublisher) in
-         // handle changes
-     }
-     ```
-     - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
-     - returns: a `ListPublisher` that broadcasts changes to the fetched results
-     */
-    public func publishList<B: SectionMonitorBuilderType>(_ clauseChain: B) -> ListPublisher<B.ObjectType> {
-
-        return self.publishList(
-            clauseChain.from,
-            clauseChain.sectionBy,
-            clauseChain.fetchClauses
-        )
-    }
 
 
-    // MARK: - Deprecated
+    // MARK: Deprecated
 
     @available(*, deprecated, renamed: "publishObject(_:)")
     public func objectPublisher<O: DynamicObject>(_ object: O) -> ObjectPublisher<O> {

Sources/DataStack+Migration.swift

@@ -613,16 +613,7 @@ extension DataStack {
             }
         }
         let fileManager = FileManager.default
-        let systemTemporaryDirectoryURL: URL
-        if #available(macOS 10.12, iOS 10.0, *) {
-
-            systemTemporaryDirectoryURL = fileManager.temporaryDirectory
-        }
-        else {
-
-            systemTemporaryDirectoryURL = URL(fileURLWithPath: NSTemporaryDirectory())
-        }
-        let temporaryDirectoryURL = systemTemporaryDirectoryURL
+        let temporaryDirectoryURL = fileManager.temporaryDirectory
             .appendingPathComponent(Bundle.main.bundleIdentifier ?? "com.CoreStore.DataStack")
             .appendingPathComponent(ProcessInfo().globallyUniqueString)
 

Sources/DataStack+Observing.swift

@@ -29,7 +29,6 @@ import CoreData
 
 // MARK: - DataStack
 
-@available(macOS 10.12, *)
 extension DataStack {
     
     /**

Sources/DataStack+Reactive.swift

@@ -0,0 +1,384 @@
+//
+//  DataStack+Reactive.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine)
+
+import Combine
+
+
+// MARK: - DataStack
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension DataStack {
+    
+    // MARK: Public
+    
+    /**
+     Combine utilities for the `DataStack` are exposed through this namespace
+     */
+    public var reactive: DataStack.ReactiveNamespace {
+        
+        return .init(self)
+    }
+    
+    // MARK: - ReactiveNamespace
+    
+    /**
+     Combine utilities for the `DataStack` are exposed through this namespace. Extend this type if you need to add other Combine Publisher utilities for `DataStack`.
+     */
+    public struct ReactiveNamespace {
+        
+        // MARK: Public
+        
+        /**
+         The `DataStack` instance
+         */
+        public let base: DataStack
+        
+        
+        // MARK: Internal
+        
+        internal init(_ base: DataStack) {
+            
+            self.base = base
+        }
+    }
+}
+
+
+// MARK: - DataStack.ReactiveNamespace
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension DataStack.ReactiveNamespace {
+    
+    // MARK: Public
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `addStorage(...)` API. Asynchronously adds a `StorageInterface` to the stack.
+     ```
+     dataStack.reactive
+         .addStorage(
+             InMemoryStore(configuration: "Config1")
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { storage in
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter storage: the storage
+     - returns: A `Future` that emits a `StorageInterface` instance added to the `DataStack`. Note that the `StorageInterface` event value may not always be the same instance as the parameter argument if a previous `StorageInterface` was already added at the same URL and with the same configuration.
+     */
+    public func addStorage<T: StorageInterface>(_ storage: T) -> Future<T, CoreStoreError> {
+        
+        return .init { (promise) in
+            
+            self.base.addStorage(
+                storage,
+                completion: { (result) in
+                    
+                    switch result {
+                    
+                    case .success(let storage):
+                        promise(.success(storage))
+                        
+                    case .failure(let error):
+                        promise(.failure(error))
+                    }
+                }
+            )
+        }
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `addStorage(...)` API. Asynchronously adds a `LocalStorage` to the stack. Migrations are also initiated by default. The event emits `DataStack.AddStoragePublisher.MigrationProgress` `enum` values.
+     ```
+     dataStack.reactive
+         .addStorage(
+             SQLiteStore(
+                 fileName: "core_data.sqlite",
+                 configuration: "Config1"
+             )
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (progress) in
+                 print("\(round(progress.fractionCompleted * 100)) %") // 0.0 ~ 1.0
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter storage: the local storage
+     - returns: A `DataStack.AddStoragePublisher` that emits a `DataStack.AddStoragePublisher.MigrationProgress` value with metadata for migration progress. Note that the `LocalStorage` event value may not always be the same instance as the parameter argument if a previous `LocalStorage` was already added at the same URL and with the same configuration.
+     */
+    public func addStorage<T: LocalStorage>(_ storage: T) -> DataStack.AddStoragePublisher<T> {
+        
+        return .init(
+            dataStack: self.base,
+            storage: storage
+        )
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `importObject(...)` API. Creates an `ImportableObject` by importing from the specified import source. The event value will be the object instance correctly associated for the `DataStack`.
+     ```
+     dataStack.reactive
+         .importObject(
+             Into<Person>(),
+             source: ["name": "John"]
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (person) in
+                 XCTAssertNotNil(person)
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter into: an `Into` clause specifying the entity type
+     - parameter source: the object to import values from
+     - returns: A `Future` that publishes the imported object. The event value, if not `nil`, will be the object instance correctly associated for the `DataStack`.
+     */
+    public func importObject<O: DynamicObject & ImportableObject>(
+        _ into: Into<O>,
+        source: O.ImportSource
+    ) -> Future<O?, CoreStoreError> {
+        
+        return .init { (promise) in
+            
+            self.base.perform(
+                asynchronous: { (transaction) -> O? in
+                    
+                    return try transaction.importObject(
+                        into,
+                        source: source
+                    )
+                },
+                success: { promise(.success($0.flatMap(self.base.fetchExisting))) },
+                failure: { promise(.failure($0)) }
+            )
+        }
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `importObject(...)` API. Updates an existing `ImportableObject` by importing values from the specified import source. The event value will be the object instance correctly associated for the `DataStack`.
+     ```
+     let existingPerson: Person = // ...
+     dataStack.reactive
+         .importObject(
+             existingPerson,
+             source: ["name": "John", "age": 30]
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (person) in
+                 XCTAssertEqual(person?.age, 30)
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter object: the object to update
+     - parameter source: the object to import values from
+     - returns: A `Future` that publishes the imported object. The event value, if not `nil`, will be the object instance correctly associated for the `DataStack`.
+     */
+    public func importObject<O: DynamicObject & ImportableObject>(
+        _ object: O,
+        source: O.ImportSource
+    ) -> Future<O?, CoreStoreError> {
+        
+        return .init { (promise) in
+            
+            self.base.perform(
+                asynchronous: { (transaction) -> O? in
+                    
+                    guard let object = transaction.edit(object) else {
+                        
+                        try transaction.cancel()
+                    }
+                    try transaction.importObject(
+                        object,
+                        source: source
+                    )
+                    return object
+                },
+                success: { promise(.success($0.flatMap(self.base.fetchExisting))) },
+                failure: { promise(.failure($0)) }
+            )
+        }
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `importUniqueObject(...)` API. Updates an existing `ImportableUniqueObject` or creates a new instance by importing from the specified import source. The event value will be the object instance correctly associated for the `DataStack`.
+     ```
+     dataStack.reactive
+         .importUniqueObject(
+             Into<Person>(),
+             source: ["name": "John", "age": 30]
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (person) in
+                 XCTAssertEqual(person?.age, 30)
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter into: an `Into` clause specifying the entity type
+     - parameter source: the object to import values from
+     - returns: A `Future` for the imported object. The event value, if not `nil`, will be the object instance correctly associated for the `DataStack`.
+     */
+    public func importUniqueObject<O: DynamicObject & ImportableUniqueObject>(
+        _ into: Into<O>,
+        source: O.ImportSource
+    ) -> Future<O?, CoreStoreError> {
+        
+        return .init { (promise) in
+            
+            self.base.perform(
+                asynchronous: { (transaction) -> O? in
+                    
+                    return try transaction.importUniqueObject(
+                        into,
+                        source: source
+                    )
+                },
+                success: { promise(.success($0.flatMap(self.base.fetchExisting))) },
+                failure: { promise(.failure($0)) }
+            )
+        }
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `importUniqueObjects(...)` API. Updates existing `ImportableUniqueObject`s or creates them by importing from the specified array of import sources. `ImportableUniqueObject` methods are called on the objects in the same order as they are in the `sourceArray`, and are returned in an array with that same order. The event values will be object instances correctly associated for the `DataStack`.
+     ```
+     dataStack.reactive
+         .importUniqueObjects(
+             Into<Person>(),
+             sourceArray: [
+                 ["name": "John"],
+                 ["name": "Bob"],
+                 ["name": "Joe"]
+             ]
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (people) in
+                 XCTAssertEqual(people?.count, 3)
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - Warning: If `sourceArray` contains multiple import sources with same ID, no merging will occur and ONLY THE LAST duplicate will be imported.
+     - parameter into: an `Into` clause specifying the entity type
+     - parameter sourceArray: the array of objects to import values from
+     - parameter preProcess: a closure that lets the caller tweak the internal `UniqueIDType`-to-`ImportSource` mapping to be used for importing. Callers can remove from/add to/update `mapping` and return the updated array from the closure.
+     - returns: A `Future` for the imported objects. The event values will be the object instances correctly associated for the `DataStack`.
+     */
+    public func importUniqueObjects<O: DynamicObject & ImportableUniqueObject, S: Sequence>(
+        _ into: Into<O>,
+        sourceArray: S,
+        preProcess: @escaping (_ mapping: [O.UniqueIDType: O.ImportSource]) throws -> [O.UniqueIDType: O.ImportSource] = { $0 }
+    ) -> Future<[O], CoreStoreError> where S.Iterator.Element == O.ImportSource {
+        
+        return .init { (promise) in
+            
+            self.base.perform(
+                asynchronous: { (transaction) -> [O] in
+                    
+                    return try transaction.importUniqueObjects(
+                        into,
+                        sourceArray: sourceArray,
+                        preProcess: preProcess
+                    )
+                },
+                success: { promise(.success(self.base.fetchExisting($0))) },
+                failure: { promise(.failure($0)) }
+            )
+        }
+    }
+    
+    /**
+     Reactive extension for `CoreStore.DataStack`'s `perform(asynchronous:...)` API. Performs a transaction asynchronously where `NSManagedObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. The event value will be the value returned from the `task` closure. Any errors thrown from inside the `task` will be wrapped in a `CoreStoreError` and reported to the completion `.failure`. To cancel/rollback changes, call `transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
+     ```
+     dataStack.reactive
+         .perform(
+             asynchronous: { (transaction) -> (inserted: Set<NSManagedObject>, deleted: Set<NSManagedObject>) in
+     
+                 // ...
+                 return (
+                     transaction.insertedObjects(),
+                     transaction.deletedObjects()
+                 )
+             }
+         )
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { value in
+                 let inserted = dataStack.fetchExisting(value0.inserted)
+                 let deleted = dataStack.fetchExisting(value0.deleted)
+                 // ...
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter task: the asynchronous closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
+     - returns: A `Future` whose event value be the value returned from the `task` closure.
+     */
+    public func perform<Output>(
+        _ asynchronous: @escaping (AsynchronousDataTransaction) throws -> Output
+    ) -> Future<Output, CoreStoreError> {
+        
+        return .init { (promise) in
+            
+            self.base.perform(
+                asynchronous: asynchronous,
+                success: { promise(.success($0)) },
+                failure: { promise(.failure($0)) }
+            )
+        }
+    }
+}
+
+#endif

Sources/DataStack+Transaction.swift

@@ -35,12 +35,18 @@ extension DataStack {
      Performs a transaction asynchronously where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. On success, the value returned from closure will be the wrapped as `.success(T)` in the `completion`'s `Result<T>`. Any errors thrown from inside the `task` will be reported as `.failure(CoreStoreError)`. To cancel/rollback changes, call `try transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
      
      - parameter task: the asynchronous closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - parameter completion: the closure executed after the save completes. The `Result` argument of the closure will either wrap the return value of `task`, or any uncaught errors thrown from within `task`. Cancelled `task`s will be indicated by `.failure(error: CoreStoreError.userCancelled)`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
      */
-    public func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, completion: @escaping (AsynchronousDataTransaction.Result<T>) -> Void) {
+    public func perform<T>(
+        asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T,
+        sourceIdentifier: Any? = nil,
+        completion: @escaping (AsynchronousDataTransaction.Result<T>) -> Void
+    ) {
         
         self.perform(
             asynchronous: task,
+            sourceIdentifier: sourceIdentifier,
             success: { completion(.success($0)) },
             failure: { completion(.failure($0)) }
         )
@@ -50,14 +56,21 @@ extension DataStack {
      Performs a transaction asynchronously where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. The changes are commited automatically after the `task` closure returns. On success, the value returned from closure will be the argument of the `success` closure. Any errors thrown from inside the `task` will be wrapped in a `CoreStoreError` and reported in the `failure` closure. To cancel/rollback changes, call `try transaction.cancel()`, which throws a `CoreStoreError.userCancelled`.
      
      - parameter task: the asynchronous closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - parameter success: the closure executed after the save succeeds. The `T` argument of the closure will be the value returned from `task`.
      - parameter failure: the closure executed if the save fails or if any errors are thrown within `task`. Cancelled `task`s will be indicated by `CoreStoreError.userCancelled`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
      */
-    public func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, success: @escaping (T) -> Void, failure: @escaping (CoreStoreError) -> Void) {
+    public func perform<T>(
+        asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T,
+        sourceIdentifier: Any? = nil,
+        success: @escaping (T) -> Void,
+        failure: @escaping (CoreStoreError) -> Void
+    ) {
         
         let transaction = AsynchronousDataTransaction(
             mainContext: self.rootSavingContext,
-            queue: self.childTransactionQueue
+            queue: self.childTransactionQueue,
+            sourceIdentifier: sourceIdentifier
         )
         transaction.transactionQueue.cs_async {
             
@@ -99,14 +112,20 @@ extension DataStack {
      
      - parameter task: the synchronous non-escaping closure where creates, updates, and deletes can be made to the transaction. Transaction blocks are executed serially in a background queue, and all changes are made from a concurrent `NSManagedObjectContext`.
      - parameter waitForAllObservers: When `true`, this method waits for all observers to be notified of the changes before returning. This results in more predictable data update order, but may risk triggering deadlocks. When `false`, this method does not wait for observers to be notified of the changes before returning. This results in lower risk for deadlocks, but the updated data may not have been propagated to the `DataStack` after returning. Defaults to `true`.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - throws: a `CoreStoreError` value indicating the failure. Cancelled `task`s will be indicated by `CoreStoreError.userCancelled`. Custom errors thrown by the user will be wrapped in `CoreStoreError.userError(error: Error)`.
      - returns: the value returned from `task`
      */
-    public func perform<T>(synchronous task: ((_ transaction: SynchronousDataTransaction) throws -> T), waitForAllObservers: Bool = true) throws -> T {
+    public func perform<T>(
+        synchronous task: ((_ transaction: SynchronousDataTransaction) throws -> T),
+        waitForAllObservers: Bool = true,
+        sourceIdentifier: Any? = nil
+    ) throws -> T {
         
         let transaction = SynchronousDataTransaction(
             mainContext: self.rootSavingContext,
-            queue: self.childTransactionQueue
+            queue: self.childTransactionQueue,
+            sourceIdentifier: sourceIdentifier
         )
         return try transaction.transactionQueue.cs_sync {
             
@@ -141,15 +160,20 @@ extension DataStack {
     /**
      Begins a non-contiguous transaction where `NSManagedObject` or `CoreStoreObject` creates, updates, and deletes can be made. This is useful for making temporary changes, such as partially filled forms.
      
-     - prameter supportsUndo: `undo()`, `redo()`, and `rollback()` methods are only available when this parameter is `true`, otherwise those method will raise an exception. Defaults to `false`. Note that turning on Undo support may heavily impact performance especially on iOS or watchOS where memory is limited.
+     - parameter supportsUndo: `undo()`, `redo()`, and `rollback()` methods are only available when this parameter is `true`, otherwise those method will raise an exception. Defaults to `false`. Note that turning on Undo support may heavily impact performance especially on iOS or watchOS where memory is limited.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - returns: a `UnsafeDataTransaction` instance where creates, updates, and deletes can be made.
      */
-    public func beginUnsafe(supportsUndo: Bool = false) -> UnsafeDataTransaction {
+    public func beginUnsafe(
+        supportsUndo: Bool = false,
+        sourceIdentifier: Any? = nil
+    ) -> UnsafeDataTransaction {
         
         return UnsafeDataTransaction(
             mainContext: self.rootSavingContext,
             queue: DispatchQueue.serial("com.coreStore.dataStack.unsafeTransactionQueue", qos: .userInitiated),
-            supportsUndo: supportsUndo
+            supportsUndo: supportsUndo,
+            sourceIdentifier: sourceIdentifier
         )
     }
     

Sources/DataStack.AddStoragePublisher.swift

@@ -0,0 +1,239 @@
+//
+//  DataStack.AddStoragePublisher.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine)
+import Combine
+import CoreData
+
+
+// MARK: - DataStack
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension DataStack {
+    
+    // MARK: - AddStoragePublisher
+    
+    /**
+     A `Publisher` that emits a `ListSnapshot` whenever changes occur in the `ListPublisher`.
+     
+     - SeeAlso: DataStack.reactive.addStorage(_:)     
+     */
+    public struct AddStoragePublisher<Storage: LocalStorage>: Publisher {
+        
+        // MARK: Internal
+        
+        internal let dataStack: DataStack
+        internal let storage: Storage
+        
+        
+        // MARK: Publisher
+        
+        public typealias Output = MigrationProgress
+        public typealias Failure = CoreStoreError
+        
+        public func receive<S: Subscriber>(subscriber: S) where S.Input == Output, S.Failure == Failure {
+            
+            subscriber.receive(
+                subscription: AddStorageSubscription(
+                    dataStack: self.dataStack,
+                    storage: self.storage,
+                    subscriber: subscriber
+                )
+            )
+        }
+        
+        // MARK: - MigrationProgress
+        
+        /**
+         A `MigrationProgress` contains info on a `LocalStorage`'s setup progress.
+         
+         - SeeAlso: DataStack.reactive.addStorage(_:)
+         */
+        public enum MigrationProgress {
+            
+            /**
+             The `LocalStorage` is currently being migrated
+             */
+            case migrating(storage: Storage, progressObject: Progress)
+            
+            /**
+             The `LocalStorage` has been added to the `DataStack` and is ready for reading and writing
+             */
+            case finished(storage: Storage, migrationRequired: Bool)
+            
+            /**
+             The fraction of the overall work completed by the migration. Returns a value between 0.0 and 1.0, inclusive.
+             */
+            public var fractionCompleted: Double {
+                
+                switch self {
+                
+                case .migrating(_, let progressObject):
+                    return progressObject.fractionCompleted
+                    
+                case .finished:
+                    return 1
+                }
+            }
+            
+            /**
+             Returns `true` if the storage was successfully added to the stack, `false` otherwise.
+             */
+            public var isCompleted: Bool {
+                
+                switch self {
+                
+                case .migrating:
+                    return false
+                    
+                case .finished:
+                    return true
+                }
+            }
+        }
+        
+        
+        // MARK: - AddStorageSubscriber
+        
+        fileprivate final class AddStorageSubscriber: Subscriber {
+            
+            // MARK: Subscriber
+            
+            typealias Failure = CoreStoreError
+            
+            func receive(subscription: Subscription) {
+                
+                subscription.request(.unlimited)
+            }
+            
+            func receive(_ input: Output) -> Subscribers.Demand {
+                
+                return .unlimited
+            }
+            
+            func receive(completion: Subscribers.Completion<Failure>) {}
+        }
+        
+        
+        // MARK: - AddStorageSubscription
+        
+        fileprivate final class AddStorageSubscription<S: Subscriber>: Subscription where S.Input == Output, S.Failure == CoreStoreError {
+            
+            // MARK: FilePrivate
+            
+            fileprivate init(
+                dataStack: DataStack,
+                storage: Storage,
+                subscriber: S
+            ) {
+                
+                self.dataStack = dataStack
+                self.storage = storage
+                self.subscriber = subscriber
+            }
+            
+            
+            // MARK: Subscription
+            
+            func request(_ demand: Subscribers.Demand) {
+                
+                guard demand > 0 else {
+                    
+                    return
+                }
+                var progress: Progress? = nil
+                progress = self.dataStack.addStorage(
+                    self.storage,
+                    completion: { [weak self] result in
+                        
+                        progress?.setProgressHandler(nil)
+                        
+                        guard
+                            let self = self,
+                            let subscriber = self.subscriber
+                        else {
+                            
+                            return
+                        }
+                        switch result {
+                        
+                        case .success(let storage):
+                            _ = subscriber.receive(
+                                .finished(
+                                    storage: storage,
+                                    migrationRequired: progress != nil
+                                )
+                            )
+                            subscriber.receive(
+                                completion: .finished
+                            )
+                            
+                        case .failure(let error):
+                            subscriber.receive(
+                                completion: .failure(error)
+                            )
+                        }
+                    }
+                )
+                if let progress = progress {
+                    
+                    progress.cs_setProgressHandler { [weak self] progress in
+                        
+                        guard
+                            let self = self,
+                            let subscriber = self.subscriber
+                        else {
+                            
+                            return
+                        }
+                        _ = subscriber.receive(
+                            .migrating(
+                                storage: self.storage,
+                                progressObject: progress
+                            )
+                        )
+                    }
+                }
+            }
+            
+            
+            // MARK: Cancellable
+            
+            func cancel() {
+                
+                self.subscriber = nil
+            }
+            
+            
+            // MARK: Private
+            
+            private let dataStack: DataStack
+            private let storage: Storage
+            private var subscriber: S?
+        }
+    }
+}
+
+#endif

Sources/DiffableDataSource.BaseAdapter.swift

@@ -116,10 +116,10 @@ extension DiffableDataSource {
                     target.reload(
                         using: changeset,
                         animated: animatingDifferences,
-                        setData: setSections
+                        setData: setSections,
+                        completion: completion
                     )
-                },
-                completion: completion
+                }
             )
         }
 
@@ -148,10 +148,21 @@ extension DiffableDataSource {
                     target.reload(
                         using: changeset,
                         animated: animatingDifferences,
-                        setData: setSections
+                        setData: setSections,
+                        completion: completion
                     )
-                },
-                completion: completion
+                }
+            )
+        }
+        
+        /**
+         Creates a new empty `ListSnapshot` suitable for building custom lists inside subclass implementations of `apply(_:animatingDifferences:completion:)`.
+         */
+        public func makeEmptySnapshot() -> ListSnapshot<O> {
+            
+            return .init(
+                diffableSnapshot: .init(),
+                context: self.dataStack.unsafeContext()
             )
         }
 
@@ -209,6 +220,25 @@ extension DiffableDataSource {
 
             return self.dispatcher.indexPath(for: itemID)
         }
+        
+        /**
+         Returns the section index title for the specified `section` if the `SectionBy` for this list has provided a `sectionIndexTransformer`
+         
+         - parameter section: the section index to search for
+         - returns: the section index title for the specified `section`, or `nil` if not found
+         */
+        public func sectionIndexTitle(for section: Int) -> String? {
+            
+            return self.dispatcher.sectionIndexTitle(for: section)
+        }
+        
+        /**
+         Returns the section index titles for all sections if the `SectionBy` for this list has provided a `sectionIndexTransformer`
+         */
+        public func sectionIndexTitlesForAllSections() -> [String?] {
+            
+            return self.dispatcher.sectionIndexTitlesForAllSections()
+        }
 
 
         // MARK: Internal

Sources/DiffableDataSource.CollectionViewAdapter-AppKit.swift

@@ -83,7 +83,12 @@ extension DiffableDataSource {
          - parameter itemProvider: a closure that configures and returns the `NSCollectionViewItem` for the object
          */
         @nonobjc
-        public init(collectionView: NSCollectionView, dataStack: DataStack, itemProvider: @escaping (NSCollectionView, IndexPath, O) -> NSCollectionViewItem?, supplementaryViewProvider: @escaping (NSCollectionView, String, IndexPath) -> NSView? = { _, _, _ in nil }) {
+        public init(
+            collectionView: NSCollectionView,
+            dataStack: DataStack,
+            itemProvider: @escaping (NSCollectionView, IndexPath, O) -> NSCollectionViewItem?,
+            supplementaryViewProvider: @escaping (NSCollectionView, String, IndexPath) -> NSView? = { _, _, _ in nil }
+        ) {
 
             self.itemProvider = itemProvider
             self.supplementaryViewProvider = supplementaryViewProvider
@@ -97,19 +102,27 @@ extension DiffableDataSource {
         // MARK: - NSCollectionViewDataSource
 
         @objc
-        public dynamic func numberOfSections(in collectionView: NSCollectionView) -> Int {
+        public dynamic func numberOfSections(
+            in collectionView: NSCollectionView
+        ) -> Int {
 
             return self.numberOfSections()
         }
 
         @objc
-        public dynamic func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
+        public dynamic func collectionView(
+            _ collectionView: NSCollectionView,
+            numberOfItemsInSection section: Int
+        ) -> Int {
 
             return self.numberOfItems(inSection: section) ?? 0
         }
 
         @objc
-        open dynamic func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
+        open dynamic func collectionView(
+            _ collectionView: NSCollectionView,
+            itemForRepresentedObjectAt indexPath: IndexPath
+        ) -> NSCollectionViewItem {
 
             guard let objectID = self.itemID(for: indexPath) else {
 
@@ -127,7 +140,11 @@ extension DiffableDataSource {
         }
 
         @objc
-        open dynamic func collectionView(_ collectionView: NSCollectionView, viewForSupplementaryElementOfKind kind: NSCollectionView.SupplementaryElementKind, at indexPath: IndexPath) -> NSView {
+        open dynamic func collectionView(
+            _ collectionView: NSCollectionView,
+            viewForSupplementaryElementOfKind kind: NSCollectionView.SupplementaryElementKind,
+            at indexPath: IndexPath
+        ) -> NSView {
 
             guard let view = self.supplementaryViewProvider(collectionView, kind, indexPath) else {
 
@@ -207,9 +224,9 @@ extension DiffableDataSource {
             self.base?.moveItem(at: indexPath, to: newIndexPath)
         }
 
-        public func performBatchUpdates(updates: () -> Void, animated: Bool) {
+        public func performBatchUpdates(updates: () -> Void, animated: Bool, completion: @escaping () -> Void) {
 
-            self.base?.animator().performBatchUpdates(updates, completionHandler: nil)
+            self.base?.animator().performBatchUpdates(updates, completionHandler: { _ in completion() })
         }
 
         public func reloadData() {
@@ -220,7 +237,7 @@ extension DiffableDataSource {
 }
 
 
-// MARK: - Deprecated
+// MARK: Deprecated
 
 extension DiffableDataSource {
 

Sources/DiffableDataSource.CollectionViewAdapter-UIKit.swift

@@ -83,7 +83,12 @@ extension DiffableDataSource {
          - parameter cellProvider: a closure that configures and returns the `UICollectionViewCell` for the object
          - parameter supplementaryViewProvider: an optional closure for providing `UICollectionReusableView` supplementary views. If not set, defaults to returning `nil`
          */
-        public init(collectionView: UICollectionView, dataStack: DataStack, cellProvider: @escaping (UICollectionView, IndexPath, O) -> UICollectionViewCell?, supplementaryViewProvider: @escaping (UICollectionView, String, IndexPath) -> UICollectionReusableView? = { _, _, _ in nil }) {
+        public init(
+            collectionView: UICollectionView,
+            dataStack: DataStack,
+            cellProvider: @escaping (UICollectionView, IndexPath, O) -> UICollectionViewCell?,
+            supplementaryViewProvider: @escaping (UICollectionView, String, IndexPath) -> UICollectionReusableView? = { _, _, _ in nil }
+        ) {
 
             self.cellProvider = cellProvider
             self.supplementaryViewProvider = supplementaryViewProvider
@@ -97,19 +102,30 @@ extension DiffableDataSource {
         // MARK: - UICollectionViewDataSource
 
         @objc
-        public dynamic func numberOfSections(in collectionView: UICollectionView) -> Int {
+        @MainActor
+        public dynamic func numberOfSections(
+            in collectionView: UICollectionView
+        ) -> Int {
 
             return self.numberOfSections()
         }
 
         @objc
-        public dynamic func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
+        @MainActor
+        public dynamic func collectionView(
+            _ collectionView: UICollectionView,
+            numberOfItemsInSection section: Int
+        ) -> Int {
 
             return self.numberOfItems(inSection: section) ?? 0
         }
 
         @objc
-        open dynamic func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
+        @MainActor
+        open dynamic func collectionView(
+            _ collectionView: UICollectionView,
+            cellForItemAt indexPath: IndexPath
+        ) -> UICollectionViewCell {
 
             guard let objectID = self.itemID(for: indexPath) else {
 
@@ -127,7 +143,12 @@ extension DiffableDataSource {
         }
 
         @objc
-        open dynamic func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
+        @MainActor
+        open dynamic func collectionView(
+            _ collectionView: UICollectionView,
+            viewForSupplementaryElementOfKind kind: String,
+            at indexPath: IndexPath
+        ) -> UICollectionReusableView {
 
             guard let view = self.supplementaryViewProvider(collectionView, kind, indexPath) else {
 
@@ -207,9 +228,9 @@ extension DiffableDataSource {
             self.base?.moveItem(at: indexPath, to: newIndexPath)
         }
 
-        public func performBatchUpdates(updates: () -> Void, animated: Bool) {
+        public func performBatchUpdates(updates: () -> Void, animated: Bool, completion: @escaping () -> Void) {
 
-            self.base?.performBatchUpdates(updates, completion: nil)
+            self.base?.performBatchUpdates(updates, completion: { _ in completion() })
         }
 
         public func reloadData() {
@@ -220,7 +241,7 @@ extension DiffableDataSource {
 }
 
 
-// MARK: - Deprecated
+// MARK: Deprecated
 
 extension DiffableDataSource {
 

Sources/DiffableDataSource.TableViewAdapter-UIKit.swift

@@ -82,7 +82,11 @@ extension DiffableDataSource {
          - parameter dataStack: the `DataStack` instance that the dataSource will fetch objects from
          - parameter cellProvider: a closure that configures and returns the `UITableViewCell` for the object
          */
-        public init(tableView: UITableView, dataStack: DataStack, cellProvider: @escaping (UITableView, IndexPath, O) -> UITableViewCell?) {
+        public init(
+            tableView: UITableView,
+            dataStack: DataStack,
+            cellProvider: @escaping (UITableView, IndexPath, O) -> UITableViewCell?
+        ) {
 
             self.cellProvider = cellProvider
             super.init(target: .init(tableView), dataStack: dataStack)
@@ -102,31 +106,48 @@ extension DiffableDataSource {
         // MARK: - UITableViewDataSource
 
         @objc
+        @MainActor
         public dynamic func numberOfSections(in tableView: UITableView) -> Int {
             
             return self.numberOfSections()
         }
 
         @objc
-        public dynamic func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        @MainActor
+        public dynamic func tableView(
+            _ tableView: UITableView,
+            numberOfRowsInSection section: Int
+        ) -> Int {
             
             return self.numberOfItems(inSection: section) ?? 0
         }
 
         @objc
-        open dynamic func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            titleForHeaderInSection section: Int
+        ) -> String? {
             
             return self.sectionID(for: section)
         }
 
         @objc
-        open dynamic func tableView(_ tableView: UITableView, titleForFooterInSection section: Int) -> String? {
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            titleForFooterInSection section: Int
+        ) -> String? {
             
             return nil
         }
         
         @objc
-        open dynamic func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            cellForRowAt indexPath: IndexPath
+        ) -> UITableViewCell {
             
             guard let objectID = self.itemID(for: indexPath) else {
                 
@@ -144,19 +165,52 @@ extension DiffableDataSource {
         }
 
         @objc
-        open dynamic func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            canEditRowAt indexPath: IndexPath
+        ) -> Bool {
 
             return true
         }
 
         @objc
-        open dynamic func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            editingStyleForRowAt indexPath: IndexPath
+        ) -> UITableViewCell.EditingStyle {
 
             return .delete
         }
 
         @objc
-        open dynamic func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {}
+        @MainActor
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            commit editingStyle: UITableViewCell.EditingStyle,
+            forRowAt indexPath: IndexPath
+        ) {}
+        
+        @objc
+        @MainActor
+        open dynamic func sectionIndexTitles(
+            for tableView: UITableView
+        ) -> [String]? {
+            
+            return nil
+        }
+        
+        @objc
+        @MainActor 
+        open dynamic func tableView(
+            _ tableView: UITableView,
+            sectionForSectionIndexTitle title: String,
+            at index: Int
+        ) -> Int {
+            
+            return index
+        }
 
 
         // MARK: Private
@@ -229,22 +283,13 @@ extension DiffableDataSource {
             self.base?.moveRow(at: indexPath, to: newIndexPath)
         }
 
-        public func performBatchUpdates(updates: () -> Void, animated: Bool) {
+        public func performBatchUpdates(updates: () -> Void, animated: Bool, completion: @escaping () -> Void) {
 
             guard let base = self.base else {
 
                 return
             }
-            if #available(iOS 11.0, tvOS 11.0, *) {
-
-                base.performBatchUpdates(updates)
-            }
-            else {
-
-                base.beginUpdates()
-                updates()
-                base.endUpdates()
-            }
+            base.performBatchUpdates(updates, completion: { _ in completion() })
         }
 
         public func reloadData() {
@@ -255,7 +300,7 @@ extension DiffableDataSource {
 }
 
 
-// MARK: - Deprecated
+// MARK: Deprecated
 
 extension DiffableDataSource {
 

Sources/DiffableDataSource.Target.swift

@@ -98,7 +98,7 @@ public protocol DiffableDataSourceTarget {
     /**
      Animates multiple insert, delete, reload, and move operations as a group.
      */
-    func performBatchUpdates(updates: () -> Void, animated: Bool)
+    func performBatchUpdates(updates: () -> Void, animated: Bool, completion: @escaping () -> Void)
 
     /**
      Reloads all sections and items.
@@ -114,9 +114,15 @@ extension DiffableDataSource.Target {
         using stagedChangeset: Internals.DiffableDataUIDispatcher<O>.StagedChangeset<C>,
         animated: Bool,
         interrupt: ((Internals.DiffableDataUIDispatcher<O>.Changeset<C>) -> Bool)? = nil,
-        setData: (C) -> Void
+        setData: (C) -> Void,
+        completion: @escaping () -> Void
     ) {
 
+        let group = DispatchGroup()
+        defer {
+
+            group.notify(queue: .main, execute: completion)
+        }
         if self.shouldSuspendBatchUpdates, let data = stagedChangeset.last?.data {
 
             setData(data)
@@ -133,6 +139,7 @@ extension DiffableDataSource.Target {
                 self.reloadData()
                 return
             }
+            group.enter()
             self.performBatchUpdates(
                 updates: {
 
@@ -206,7 +213,8 @@ extension DiffableDataSource.Target {
                         )
                     }
                 },
-                animated: animated
+                animated: animated,
+                completion: group.leave
             )
         }
     }

Sources/DiffableDataSourceSnapshotProtocol.swift

@@ -44,19 +44,30 @@ internal protocol DiffableDataSourceSnapshotProtocol {
     func indexOfItem(_ identifier: NSManagedObjectID) -> Int?
     func indexOfSection(_ identifier: String) -> Int?
 
-    mutating func appendItems(_ identifiers: [NSManagedObjectID], toSection sectionIdentifier: String?)
-    mutating func insertItems(_ identifiers: [NSManagedObjectID], beforeItem beforeIdentifier: NSManagedObjectID)
-    mutating func insertItems(_ identifiers: [NSManagedObjectID], afterItem afterIdentifier: NSManagedObjectID)
-    mutating func deleteItems(_ identifiers: [NSManagedObjectID])
+    mutating func appendItems<C: Collection>(_ identifiers: C, toSection sectionIdentifier: String?) where C.Element == NSManagedObjectID
+    mutating func insertItems<C: Collection>(_ identifiers: C, beforeItem beforeIdentifier: NSManagedObjectID) where C.Element == NSManagedObjectID
+    mutating func insertItems<C: Collection>(_ identifiers: C, afterItem afterIdentifier: NSManagedObjectID) where C.Element == NSManagedObjectID
+    mutating func deleteItems<C: Collection>(_ identifiers: C) where C.Element == NSManagedObjectID
     mutating func deleteAllItems()
     mutating func moveItem(_ identifier: NSManagedObjectID, beforeItem toIdentifier: NSManagedObjectID)
     mutating func moveItem(_ identifier: NSManagedObjectID, afterItem toIdentifier: NSManagedObjectID)
-    mutating func reloadItems(_ identifiers: [NSManagedObjectID])
-    mutating func appendSections(_ identifiers: [String])
-    mutating func insertSections(_ identifiers: [String], beforeSection toIdentifier: String)
-    mutating func insertSections(_ identifiers: [String], afterSection toIdentifier: String)
-    mutating func deleteSections(_ identifiers: [String])
+    mutating func reloadItems<C: Collection>(_ identifiers: C) where C.Element == NSManagedObjectID
+    mutating func appendSections<C: Collection>(_ identifiers: C) where C.Element == String
+    mutating func insertSections<C: Collection>(_ identifiers: C, beforeSection toIdentifier: String) where C.Element == String
+    mutating func insertSections<C: Collection>(_ identifiers: C, afterSection toIdentifier: String) where C.Element == String
+    mutating func deleteSections<C: Collection>(_ identifiers: C) where C.Element == String
     mutating func moveSection(_ identifier: String, beforeSection toIdentifier: String)
     mutating func moveSection(_ identifier: String, afterSection toIdentifier: String)
-    mutating func reloadSections(_ identifiers: [String])
+    mutating func reloadSections<C: Collection>(_ identifiers: C) where C.Element == String
+    
+    mutating func unsafeAppendItems<C: Collection>(_ identifiers: C, toSectionAt sectionIndex: Int) where C.Element == NSManagedObjectID
+    mutating func unsafeInsertItems<C: Collection>(_ identifiers: C, at indexPath: IndexPath) where C.Element == NSManagedObjectID
+    mutating func unsafeDeleteItems<C: Collection>(at indexPaths: C) where C.Element == IndexPath
+    mutating func unsafeMoveItem(at indexPath: IndexPath, to newIndexPath: IndexPath)
+    mutating func unsafeReloadItems<C: Collection>(at indexPaths: C) where C.Element == IndexPath
+    mutating func unsafeInsertSections<C: Collection>(_ identifiers: C, at sectionIndex: Int) where C.Element == String
+    mutating func unsafeDeleteSections<C: Collection>(at sectionIndices: C) where C.Element == Int
+    mutating func unsafeMoveSection(at sectionIndex: Int, to newSectionIndex: Int)
+    mutating func unsafeReloadSections<C: Collection>(at sectionIndices: C) where C.Element == Int
+    
 }

Sources/Entity.swift

@@ -70,7 +70,6 @@ public final class Entity<O: CoreStoreObject>: DynamicEntity {
      - parameter indexes: the compound indexes for the entity as an array of arrays. The arrays contained in the returned array contain `KeyPath`s to properties of the entity.
      - parameter uniqueConstraints: sets uniqueness constraints for the entity. A uniqueness constraint is a set of one or more `KeyPath`s whose value must be unique over the set of instances of that entity. This value forms part of the entity's version hash. Uniqueness constraint violations can be computationally expensive to handle. It is highly suggested that there be only one uniqueness constraint per entity hierarchy. Uniqueness constraints must be defined at the highest level possible, and CoreStore will raise an assertion failure if unique constraints are added to a sub entity.
      */
-    @available(macOS 10.11, *)
     public convenience init(_ entityName: String, isAbstract: Bool = false, versionHashModifier: String? = nil, indexes: [[PartialKeyPath<O>]] = [], uniqueConstraints: [[PartialKeyPath<O>]]) {
         
         self.init(
@@ -116,7 +115,6 @@ public final class Entity<O: CoreStoreObject>: DynamicEntity {
      - parameter indexes: the compound indexes for the entity as an array of arrays. The arrays contained in the returned array contain KeyPath's to properties of the entity.
      - parameter uniqueConstraints: sets uniqueness constraints for the entity. A uniqueness constraint is a set of one or more `KeyPath`s whose value must be unique over the set of instances of that entity. This value forms part of the entity's version hash. Uniqueness constraint violations can be computationally expensive to handle. It is highly suggested that there be only one uniqueness constraint per entity hierarchy. Uniqueness constraints must be defined at the highest level possible, and CoreStore will raise an assertion failure if unique constraints are added to a sub entity.
      */
-    @available(macOS 10.11, *)
     public init(_ type: O.Type, _ entityName: String, isAbstract: Bool = false, versionHashModifier: String? = nil, indexes: [[PartialKeyPath<O>]] = [], uniqueConstraints: [[PartialKeyPath<O>]]) {
         
         let meta = O.meta

Sources/FieldCoders.NSCoding.swift

@@ -47,17 +47,10 @@ extension FieldCoders {
 
                 return nil
             }
-            if #available(iOS 11.0, macOS 10.13, watchOS 4.0, tvOS 11.0, *) {
-
-                return try! NSKeyedArchiver.archivedData(
-                    withRootObject: fieldValue,
-                    requiringSecureCoding: self.requiresSecureCoding
-                )
-            }
-            else {
-
-                return NSKeyedArchiver.archivedData(withRootObject: fieldValue)
-            }
+            return try! NSKeyedArchiver.archivedData(
+                withRootObject: fieldValue,
+                requiringSecureCoding: self.requiresSecureCoding
+            )
         }
 
         public static func decodeFromStoredData(_ data: Data?) -> FieldStoredValue? {
@@ -66,14 +59,10 @@ extension FieldCoders {
 
                 return nil
             }
-            if #available(iOS 11.0, macOS 10.13, watchOS 4.0, tvOS 11.0, *) {
-
-                return try! NSKeyedUnarchiver.unarchivedObject(ofClass: FieldStoredValue.self, from: data)
-            }
-            else {
-
-                return NSKeyedUnarchiver.unarchiveObject(with: data) as! FieldStoredValue?
-            }
+            return try! NSKeyedUnarchiver.unarchivedObject(
+                ofClass: FieldStoredValue.self,
+                from: data
+            )
         }
 
 

Sources/ForEach+SwiftUI.swift

@@ -0,0 +1,201 @@
+//
+//  ForEach+SwiftUI.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine) && canImport(SwiftUI)
+
+import Combine
+import SwiftUI
+
+
+// MARK: - ForEach
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
+extension ForEach where Content: View {
+    
+    // MARK: Public
+    
+    /**
+     Creates an instance that creates views for each object in a collection of `ObjectSnapshot`s. The objects' `NSManagedObjectID` are used as the identifier
+     ```
+     let people: [ObjectSnapshot<Person>]
+     
+     var body: some View {
+     
+        List {
+            
+            ForEach(self.people) { person in
+
+                ProfileView(person)
+            }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter objectSnapshots: The collection of `ObjectSnapshot`s that the `ForEach` instance uses to create views dynamically
+     - parameter content: The view builder that receives an `ObjectPublisher` instance and creates views dynamically.
+     */
+    public init<O: DynamicObject>(
+        _ objectSnapshots: Data,
+        @ViewBuilder content: @escaping (ObjectSnapshot<O>) -> Content
+    ) where Data.Element == ObjectSnapshot<O>, ID == O.ObjectID {
+        
+        self.init(objectSnapshots, id: \.cs_objectID, content: content)
+    }
+
+    /**
+     Creates an instance that creates views for each object in a `ListSnapshot`.
+     ```
+     @ListState
+     var people: ListSnapshot<Person>
+     
+     var body: some View {
+     
+        List {
+            
+             ForEach(objectIn: self.people) { person in
+
+                 ProfileView(person)
+             }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter listSnapshot: The `ListSnapshot` that the `ForEach` instance uses to create views dynamically
+     - parameter content: The view builder that receives an `ObjectPublisher` instance and creates views dynamically.
+     */
+    public init<O: DynamicObject>(
+        objectIn listSnapshot: Data,
+        @ViewBuilder content: @escaping (ObjectPublisher<O>) -> Content
+    ) where Data == ListSnapshot<O>, ID == O.ObjectID {
+        
+        self.init(listSnapshot, id: \.cs_objectID, content: content)
+    }
+    
+    /**
+     Creates an instance that creates views for each object in a collection of `ObjectPublisher`s.
+     ```
+     let people: [ObjectPublisher<Person>]
+     
+     var body: some View {
+     
+        List {
+            
+            ForEach(objectIn: self.people) { person in
+
+                ProfileView(person)
+            }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter objectPublishers: The collection of `ObjectPublisher`s that the `ForEach` instance uses to create views dynamically
+     - parameter content: The view builder that receives an `ObjectPublisher` instance and creates views dynamically.
+     */
+    public init<O: DynamicObject>(
+        objectIn objectPublishers: Data,
+        @ViewBuilder content: @escaping (ObjectPublisher<O>) -> Content
+    ) where Data.Element == ObjectPublisher<O>, ID == O.ObjectID {
+        
+        self.init(objectPublishers, id: \.cs_objectID, content: content)
+    }
+    
+    /**
+     Creates an instance that creates views for `ListSnapshot` sections.
+     ```
+     @ListState
+     var people: ListSnapshot<Person>
+     
+     var body: some View {
+     
+        List {
+            
+            ForEach(sectionIn: self.people) { section in
+                
+                Section(header: Text(section.sectionID)) {
+
+                    ForEach(objectIn: section) { person in
+
+                        ProfileView(person)
+                    }
+                }
+            }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter listSnapshot: The `ListSnapshot` that the `ForEach` instance uses to create views dynamically
+     - parameter content: The view builder that receives a `ListSnapshot.SectionInfo` instance and creates views dynamically.
+     */
+    public init<O: DynamicObject>(
+        sectionIn listSnapshot: ListSnapshot<O>,
+        @ViewBuilder content: @escaping (ListSnapshot<O>.SectionInfo) -> Content
+    ) where Data == [ListSnapshot<O>.SectionInfo], ID == ListSnapshot<O>.SectionID {
+        
+        let sections = listSnapshot.sections()
+        self.init(sections, id: \.sectionID, content: content)
+    }
+    
+    /**
+     Creates an instance that creates views for each object in a `ListSnapshot.SectionInfo`.
+     ```
+     @ListState
+     var people: ListSnapshot<Person>
+     
+     var body: some View {
+     
+        List {
+            
+            ForEach(sectionIn: self.people) { section in
+                
+                Section(header: Text(section.sectionID)) {
+
+                    ForEach(objectIn: section) { person in
+
+                        ProfileView(person)
+                    }
+                }
+            }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter sectionInfo: The `ListSnapshot.SectionInfo` that the `ForEach` instance uses to create views dynamically
+     - parameter content: The view builder that receives an `ObjectPublisher` instance and creates views dynamically.
+     */
+    public init<O: DynamicObject>(
+        objectIn sectionInfo: Data,
+        @ViewBuilder content: @escaping (ObjectPublisher<O>) -> Content
+    ) where Data == ListSnapshot<O>.SectionInfo, ID == O.ObjectID {
+        
+        self.init(sectionInfo, id: \.cs_objectID, content: content)
+    }
+}
+
+#endif

Sources/From+Querying.swift

@@ -71,7 +71,10 @@ extension From {
      - parameter args: the arguments for `format`
      - returns: a `FetchChainBuilder` with a predicate using the specified string format and arguments
      */
-    public func `where`(format: String, _ args: Any...) -> FetchChainBuilder<O> {
+    public func `where`(
+        format: String,
+        _ args: Any...
+    ) -> FetchChainBuilder<O> {
         
         return self.fetchChain(appending: Where<O>(format, argumentArray: args))
     }
@@ -83,7 +86,10 @@ extension From {
      - parameter argumentArray: the arguments for `format`
      - returns: a `FetchChainBuilder` with a predicate using the specified string format and arguments
      */
-    public func `where`(format: String, argumentArray: [Any]?) -> FetchChainBuilder<O> {
+    public func `where`(
+        format: String,
+        argumentArray: [Any]?
+    ) -> FetchChainBuilder<O> {
         
         return self.fetchChain(appending: Where<O>(format, argumentArray: argumentArray))
     }
@@ -106,7 +112,10 @@ extension From {
      - parameter sortKeys: a series of other `SortKey`s
      - returns: a `FetchChainBuilder` with a series of `SortKey`s
      */
-    public func orderBy(_ sortKey: OrderBy<O>.SortKey, _ sortKeys: OrderBy<O>.SortKey...) -> FetchChainBuilder<O> {
+    public func orderBy(
+        _ sortKey: OrderBy<O>.SortKey,
+        _ sortKeys: OrderBy<O>.SortKey...
+    ) -> FetchChainBuilder<O> {
         
         return self.fetchChain(appending: OrderBy<O>([sortKey] + sortKeys))
     }
@@ -178,7 +187,11 @@ extension From {
      - parameter selectTerms: a series of `SelectTerm`s
      - returns: a `QueryChainBuilder` that starts with a `Select` clause created from the specified `SelectTerm`s
      */
-    public func select<R>(_ resultType: R.Type, _ selectTerm: SelectTerm<O>, _ selectTerms: SelectTerm<O>...) -> QueryChainBuilder<O, R> {
+    public func select<R>(
+        _ resultType: R.Type,
+        _ selectTerm: SelectTerm<O>,
+        _ selectTerms: SelectTerm<O>...
+    ) -> QueryChainBuilder<O, R> {
         
         return self.select(resultType, [selectTerm] + selectTerms)
     }
@@ -190,7 +203,10 @@ extension From {
      - parameter selectTerms: a series of `SelectTerm`s
      - returns: a `QueryChainBuilder` that starts with a `Select` clause created from the specified `SelectTerm`s
      */
-    public func select<R>(_ resultType: R.Type, _ selectTerms: [SelectTerm<O>]) -> QueryChainBuilder<O, R> {
+    public func select<R>(
+        _ resultType: R.Type,
+        _ selectTerms: [SelectTerm<O>]
+    ) -> QueryChainBuilder<O, R> {
         
         return .init(
             from: self,
@@ -205,7 +221,6 @@ extension From {
      - parameter clause: the `SectionBy` to be used by the `ListMonitor`
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy(_ clause: SectionBy<O>) -> SectionMonitorChainBuilder<O> {
         
         return .init(
@@ -221,26 +236,30 @@ extension From {
      - parameter sectionKeyPath: the key path to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy(_ sectionKeyPath: KeyPathString) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(sectionKeyPath, { $0 })
+        return self.sectionBy(sectionKeyPath, sectionIndexTransformer: { _ in nil })
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the key path to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy(_ sectionKeyPath: KeyPathString, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy(
+        _ sectionKeyPath: KeyPathString,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
         return .init(
             from: self,
-            sectionBy: .init(sectionKeyPath, sectionIndexTransformer),
+            sectionBy: .init(
+                sectionKeyPath,
+                sectionIndexTransformer: sectionIndexTransformer
+            ),
             fetchClauses: []
         )
     }
@@ -257,6 +276,21 @@ extension From {
         
         return .init(from: self, fetchClauses: Array(clauses))
     }
+    
+    
+    // MARK: Deprecated
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy(
+        _ sectionKeyPath: KeyPathString,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
 }
 
 
@@ -281,24 +315,46 @@ extension From where O: NSManagedObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, T>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(sectionKeyPath._kvcKeyPathString!, { $0 })
+        return self.sectionBy(
+            sectionKeyPath._kvcKeyPathString!,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, T>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, T>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(sectionKeyPath._kvcKeyPathString!, sectionIndexTransformer)
+        return self.sectionBy(
+            sectionKeyPath._kvcKeyPathString!,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    
+    // MARK: Deprecated
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, T>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath._kvcKeyPathString!,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
 }
 
@@ -368,10 +424,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Stored<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
@@ -380,10 +438,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Virtual<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
 
     /**
@@ -392,10 +452,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Coded<T>>) -> SectionMonitorChainBuilder<O> {
 
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
@@ -404,10 +466,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, ValueContainer<O>.Required<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
@@ -416,10 +480,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, ValueContainer<O>.Optional<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
@@ -428,10 +494,12 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Required<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
     
     /**
@@ -440,108 +508,232 @@ extension From where O: CoreStoreObject {
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
     public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Optional<T>>) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, { $0 })
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: { _ in nil }
+        )
     }
 
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
 
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Stored<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Stored<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
 
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
 
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
 
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Virtual<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Virtual<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
 
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
 
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
 
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, FieldContainer<O>.Coded<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Coded<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
 
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, ValueContainer<O>.Required<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, ValueContainer<O>.Required<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, ValueContainer<O>.Optional<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, ValueContainer<O>.Optional<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Required<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Required<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
     
     /**
-     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section name
+     Creates a `SectionMonitorChainBuilder` with the key path to use to group `ListMonitor` objects into sections, and a closure to transform the value for the key path to an appropriate section index title
      
      - Important: Some utilities (such as `ListMonitor`s) may keep `SectionBy`s in memory and may thus introduce retain cycles if reference captures are not handled properly.
      - parameter sectionKeyPath: the `KeyPath` to use to group the objects into sections
-     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section name
+     - parameter sectionIndexTransformer: a closure to transform the value for the key path to an appropriate section index title
      - returns: a `SectionMonitorChainBuilder` that is sectioned by the specified key path
      */
-    @available(macOS 10.12, *)
-    public func sectionBy<T>(_ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Optional<T>>, _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> SectionMonitorChainBuilder<O> {
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Optional<T>>,
+        sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
         
-        return self.sectionBy(O.meta[keyPath: sectionKeyPath].keyPath, sectionIndexTransformer)
+        return self.sectionBy(
+            O.meta[keyPath: sectionKeyPath].keyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    
+    // MARK: Deprecated
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Stored<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Virtual<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, FieldContainer<O>.Coded<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, ValueContainer<O>.Required<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, ValueContainer<O>.Optional<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Required<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
+    }
+    
+    @available(*, deprecated, renamed: "sectionBy(_:sectionIndexTransformer:)")
+    public func sectionBy<T>(
+        _ sectionKeyPath: KeyPath<O, TransformableContainer<O>.Optional<T>>,
+        _ sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?
+    ) -> SectionMonitorChainBuilder<O> {
+        
+        return self.sectionBy(
+            sectionKeyPath,
+            sectionIndexTransformer: sectionIndexTransformer
+        )
     }
 }
 
@@ -1004,7 +1196,6 @@ extension QueryChainBuilder where O: CoreStoreObject {
 
 // MARK: - SectionMonitorChainBuilder
 
-@available(macOS 10.12, *)
 extension SectionMonitorChainBuilder {
     
     /**
@@ -1156,7 +1347,6 @@ extension SectionMonitorChainBuilder {
 
 // MARK: - SectionMonitorChainBuilder where O: CoreStoreObject
 
-@available(macOS 10.12, *)
 extension SectionMonitorChainBuilder where O: CoreStoreObject {
     
     /**

Sources/Internals.AnyFieldCoder.swift

@@ -77,27 +77,42 @@ extension Internals {
             let transformerName = self.transformerName
             if #available(iOS 12.0, tvOS 12.0, watchOS 5.0, macOS 10.14, *) {
 
-                if transformerName == .secureUnarchiveFromDataTransformerName {
+                switch transformerName {
 
+                case .secureUnarchiveFromDataTransformerName,
+                     .isNotNilTransformerName,
+                     .isNilTransformerName,
+                     .negateBooleanTransformerName:
                     return
+
+                case let transformerName:
+                    Self.cachedCoders[transformerName] = self
+
+                    Foundation.ValueTransformer.setValueTransformer(
+                        self.transformer,
+                        forName: transformerName
+                    )
                 }
             }
-            switch transformerName {
+            else {
+                
+                switch transformerName {
 
-            case .keyedUnarchiveFromDataTransformerName,
-                 .unarchiveFromDataTransformerName,
-                 .isNotNilTransformerName,
-                 .isNilTransformerName,
-                 .negateBooleanTransformerName:
-                return
+                case .keyedUnarchiveFromDataTransformerName,
+                     .unarchiveFromDataTransformerName,
+                     .isNotNilTransformerName,
+                     .isNilTransformerName,
+                     .negateBooleanTransformerName:
+                    return
 
-            case let transformerName:
-                Self.cachedCoders[transformerName] = self
+                case let transformerName:
+                    Self.cachedCoders[transformerName] = self
 
-                Foundation.ValueTransformer.setValueTransformer(
-                    self.transformer,
-                    forName: transformerName
-                )
+                    Foundation.ValueTransformer.setValueTransformer(
+                        self.transformer,
+                        forName: transformerName
+                    )
+                }
             }
         }
 

Sources/Internals.Closure.swift

@@ -34,7 +34,10 @@ extension Internals {
     
     internal final class Closure<T, U> {
         
-        // MARK: FilePrivate
+        // MARK: Internal
+        
+        internal typealias Arguments = T
+        internal typealias Result = U
         
         internal init(_ closure: @escaping (T) -> U) {
             

Sources/Internals.CoreStoreFetchRequest.swift

@@ -68,22 +68,8 @@ extension Internals {
             }
             set {
 
-                if #available(iOS 11.0, macOS 10.13, watchOS 4.0, tvOS 11.0, *) {
-
-                    self.copiedAffectedStores = (newValue as NSArray?)?.copy() as! NSArray?
-                    super.affectedStores = newValue
-                    return
-                }
-                // Bugfix for NSFetchRequest messing up memory management for `affectedStores`
-                // http://stackoverflow.com/questions/14396375/nsfetchedresultscontroller-crashes-in-ios-6-if-affectedstores-is-specified
-                if let releaseArray = self.releaseArray {
-
-                    releaseArray.release()
-                    self.releaseArray = nil
-                }
                 self.copiedAffectedStores = (newValue as NSArray?)?.copy() as! NSArray?
                 super.affectedStores = newValue
-                self.releaseArray = (super.affectedStores as NSArray?).map(Unmanaged<NSArray>.passRetained(_:))
             }
         }
 

Sources/Internals.CoreStoreFetchedResultsController.swift

@@ -33,7 +33,6 @@ extension Internals {
     
     // MARK: - CoreStoreFetchedResultsController
     
-    @available(macOS 10.12, *)
     internal final class CoreStoreFetchedResultsController: NSFetchedResultsController<NSManagedObject> {
         
         // MARK: Internal

Sources/Internals.DiffableDataSourceSnapshot.swift

@@ -47,10 +47,16 @@ extension Internals {
 
         // MARK: Internal
 
-        init(sections: [NSFetchedResultsSectionInfo], fetchOffset: Int, fetchLimit: Int) {
+        init(
+            sections: [NSFetchedResultsSectionInfo],
+            sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?,
+            fetchOffset: Int,
+            fetchLimit: Int
+        ) {
 
             self.structure = .init(
                 sections: sections,
+                sectionIndexTransformer: sectionIndexTransformer,
                 fetchOffset: Swift.max(0, fetchOffset),
                 fetchLimit: (fetchLimit > 0) ? fetchLimit : nil
             )
@@ -194,7 +200,7 @@ extension Internals {
             self.structure.insert(itemIDs: identifiers, after: afterIdentifier)
         }
 
-        mutating func deleteItems<S: Sequence>(_ identifiers: S) where S.Element == NSManagedObjectID {
+        mutating func deleteItems<C: Collection>(_ identifiers: C) where C.Element == NSManagedObjectID {
 
             self.structure.remove(itemIDs: identifiers)
         }
@@ -214,7 +220,7 @@ extension Internals {
             self.structure.move(itemID: identifier, after: toIdentifier)
         }
 
-        mutating func reloadItems<S: Sequence>(_ identifiers: S) where S.Element == NSManagedObjectID {
+        mutating func reloadItems<C: Collection>(_ identifiers: C) where C.Element == NSManagedObjectID {
 
             self.structure.update(itemIDs: identifiers)
         }
@@ -234,7 +240,7 @@ extension Internals {
             self.structure.insert(sectionIDs: identifiers, after: toIdentifier)
         }
 
-        mutating func deleteSections<S: Sequence>(_ identifiers: S) where S.Element == String {
+        mutating func deleteSections<C: Collection>(_ identifiers: C) where C.Element == String {
 
             self.structure.remove(sectionIDs: identifiers)
         }
@@ -249,10 +255,55 @@ extension Internals {
             self.structure.move(sectionID: identifier, after: toIdentifier)
         }
 
-        mutating func reloadSections<S: Sequence>(_ identifiers: S) where S.Element == String {
+        mutating func reloadSections<C: Collection>(_ identifiers: C) where C.Element == String {
 
             self.structure.update(sectionIDs: identifiers)
         }
+        
+        mutating func unsafeAppendItems<C: Collection>(_ identifiers: C, toSectionAt sectionIndex: Int) where C.Element == NSManagedObjectID {
+            
+            self.structure.unsafeAppend(identifiers, toSectionAt: sectionIndex)
+        }
+        
+        mutating func unsafeInsertItems<C: Collection>(_ identifiers: C, at indexPath: IndexPath) where C.Element == NSManagedObjectID {
+            
+            self.structure.unsafeInsert(itemIDs: identifiers, at: indexPath)
+        }
+        
+        mutating func unsafeDeleteItems<C: Collection>(at indexPaths: C) where C.Element == IndexPath {
+            
+            self.structure.unsafeRemove(itemsAt: indexPaths)
+        }
+        
+        mutating func unsafeMoveItem(at indexPath: IndexPath, to newIndexPath: IndexPath) {
+            
+            self.structure.unsafeMove(itemAt: indexPath, to: newIndexPath)
+        }
+        
+        mutating func unsafeReloadItems<C: Collection>(at indexPaths: C) where C.Element == IndexPath {
+            
+            self.structure.unsafeUpdate(itemsAt: indexPaths)
+        }
+        
+        mutating func unsafeInsertSections<C: Collection>(_ identifiers: C, at sectionIndex: Int) where C.Element == String {
+            
+            self.structure.unsafeInsert(identifiers, at: sectionIndex)
+        }
+        
+        mutating func unsafeDeleteSections<C: Collection>(at sectionIndices: C) where C.Element == Int {
+            
+            self.structure.unsafeRemove(sectionsAt: sectionIndices)
+        }
+        
+        mutating func unsafeMoveSection(at sectionIndex: Int, to newSectionIndex: Int) {
+            
+            self.structure.unsafeMove(sectionAt: sectionIndex, to: newSectionIndex)
+        }
+        
+        mutating func unsafeReloadSections<C: Collection>(at sectionIndices: C) where C.Element == Int {
+            
+            self.structure.unsafeUpdate(sectionsAt: sectionIndices)
+        }
 
 
         // MARK: Private
@@ -264,11 +315,18 @@ extension Internals {
 
         internal struct Section: DifferentiableSection, Equatable {
 
+            let indexTitle: String?
             var isReloaded: Bool
 
-            init(differenceIdentifier: String, items: [Item] = [], isReloaded: Bool = false) {
+            init(
+                differenceIdentifier: String,
+                indexTitle: String?,
+                items: [Item] = [],
+                isReloaded: Bool = false
+            ) {
                 
                 self.differenceIdentifier = differenceIdentifier
+                self.indexTitle = indexTitle
                 self.elements = items
                 self.isReloaded = isReloaded
             }
@@ -292,6 +350,7 @@ extension Internals {
 
                 self.init(
                     differenceIdentifier: source.differenceIdentifier,
+                    indexTitle: source.indexTitle,
                     items: Array(elements),
                     isReloaded: source.isReloaded
                 )
@@ -329,16 +388,23 @@ extension Internals {
 
             // MARK: Internal
 
+            let sectionIndexTransformer: (_ sectionName: String?) -> String?
             var sections: [Section]
             private(set) var reloadedItems: Set<NSManagedObjectID>
 
             init() {
 
+                self.sectionIndexTransformer = { _ in nil }
                 self.sections = []
                 self.reloadedItems = []
             }
 
-            init(sections: [NSFetchedResultsSectionInfo], fetchOffset: Int, fetchLimit: Int?) {
+            init(
+                sections: [NSFetchedResultsSectionInfo],
+                sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?,
+                fetchOffset: Int,
+                fetchLimit: Int?
+            ) {
 
                 let sliceItems: (_ array: [Any], _ offset: Int) -> Array<Any>.SubSequence
                 if let fetchLimit = fetchLimit {
@@ -373,9 +439,14 @@ extension Internals {
                         continue
                     }
                     newSections.append(
-                        Section(differenceIdentifier: section.name, items: items)
+                        Section(
+                            differenceIdentifier: section.name,
+                            indexTitle: section.indexTitle,
+                            items: items
+                        )
                     )
                 }
+                self.sectionIndexTransformer = sectionIndexTransformer
                 self.sections = newSections
                 self.reloadedItems = []
             }
@@ -406,13 +477,23 @@ extension Internals {
                 }
                 return self.sections[sectionIndex].elements.map({ $0.differenceIdentifier })
             }
+            
+            func unsafeItem(at indexPath: IndexPath) -> NSManagedObjectID {
+                
+                return self.sections[indexPath.section]
+                    .elements[indexPath.item]
+                    .differenceIdentifier
+            }
 
             func section(containing itemID: NSManagedObjectID) -> String? {
 
                 return self.itemPositionMap(itemID)?.section.differenceIdentifier
             }
 
-            mutating func append<C: Collection>(itemIDs: C, to sectionID: String?) where C.Element == NSManagedObjectID {
+            mutating func append<C: Collection>(
+                itemIDs: C,
+                to sectionID: String?
+            ) where C.Element == NSManagedObjectID {
 
                 let index: Array<Section>.Index
                 if let sectionID = sectionID {
@@ -435,8 +516,30 @@ extension Internals {
                 let items = itemIDs.lazy.map({ Item(differenceIdentifier: $0) })
                 self.sections[index].elements.append(contentsOf: items)
             }
+            
+            mutating func unsafeAppend<C: Collection>(
+                _ itemIDs: C,
+                toSectionAt sectionIndex: Int?
+            ) where C.Element == NSManagedObjectID  {
+                
+                let index: Array<Section>.Index
+                if let sectionIndex = sectionIndex {
 
-            mutating func insert<C: Collection>(itemIDs: C, before beforeItemID: NSManagedObjectID) where C.Element == NSManagedObjectID {
+                    index = sectionIndex
+                }
+                else {
+                    
+                    let section = self.sections
+                    index = section.index(before: section.endIndex)
+                }
+                let items = itemIDs.lazy.map({ Item(differenceIdentifier: $0) })
+                self.sections[index].elements.append(contentsOf: items)
+            }
+
+            mutating func insert<C: Collection>(
+                itemIDs: C,
+                before beforeItemID: NSManagedObjectID
+            ) where C.Element == NSManagedObjectID {
 
                 guard let itemPosition = self.itemPositionMap(beforeItemID) else {
 
@@ -447,7 +550,10 @@ extension Internals {
                     .insert(contentsOf: items, at: itemPosition.itemRelativeIndex)
             }
 
-            mutating func insert<C: Collection>(itemIDs: C, after afterItemID: NSManagedObjectID) where C.Element == NSManagedObjectID {
+            mutating func insert<C: Collection>(
+                itemIDs: C,
+                after afterItemID: NSManagedObjectID
+            ) where C.Element == NSManagedObjectID {
 
                 guard let itemPosition = self.itemPositionMap(afterItemID) else {
 
@@ -459,6 +565,16 @@ extension Internals {
                 self.sections[itemPosition.sectionIndex].elements
                     .insert(contentsOf: items, at: itemIndex)
             }
+            
+            mutating func unsafeInsert<C: Collection>(
+                itemIDs: C,
+                at indexPath: IndexPath
+            ) where C.Element == NSManagedObjectID {
+                
+                let items = itemIDs.lazy.map({ Item(differenceIdentifier: $0) })
+                self.sections[indexPath.section].elements
+                    .insert(contentsOf: items, at: indexPath.item)
+            }
 
             mutating func remove<S: Sequence>(itemIDs: S) where S.Element == NSManagedObjectID {
 
@@ -482,6 +598,23 @@ extension Internals {
                     }
                 }
             }
+            
+            mutating func unsafeRemove<S: Sequence>(itemsAt indexPaths: S) where S.Element == IndexPath {
+                
+                var removeIndexSetMap: [Int: IndexSet] = [:]
+                for indexPath in indexPaths {
+                    
+                    removeIndexSetMap[indexPath.section, default: []]
+                        .insert(indexPath.item)
+                }
+                for (sectionIndex, removeIndexSet) in removeIndexSetMap {
+
+                    for range in removeIndexSet.rangeView.reversed() {
+                        
+                        self.sections[sectionIndex].elements.removeSubrange(range)
+                    }
+                }
+            }
 
             mutating func removeAllItems() {
 
@@ -496,7 +629,10 @@ extension Internals {
                 self.sections.removeAll(where: { $0.elements.isEmpty })
             }
 
-            mutating func move(itemID: NSManagedObjectID, before beforeItemID: NSManagedObjectID) {
+            mutating func move(
+                itemID: NSManagedObjectID,
+                before beforeItemID: NSManagedObjectID
+            ) {
 
                 guard let removed = self.remove(itemID: itemID) else {
 
@@ -510,7 +646,10 @@ extension Internals {
                     .insert(removed, at: itemPosition.itemRelativeIndex)
             }
 
-            mutating func move(itemID: NSManagedObjectID, after afterItemID: NSManagedObjectID) {
+            mutating func move(
+                itemID: NSManagedObjectID,
+                after afterItemID: NSManagedObjectID
+            ) {
 
                 guard let removed = self.remove(itemID: itemID) else {
 
@@ -525,6 +664,17 @@ extension Internals {
                 self.sections[itemPosition.sectionIndex].elements
                     .insert(removed, at: itemIndex)
             }
+            
+            mutating func unsafeMove(
+                itemAt indexPath: IndexPath,
+                to newIndexPath: IndexPath
+            ) {
+                
+                let itemID = self.sections[indexPath.section].elements
+                    .remove(at: indexPath.item)
+                self.sections[newIndexPath.section].elements
+                    .insert(itemID, at: newIndexPath.item)
+            }
 
             mutating func update<S: Sequence>(itemIDs: S) where S.Element == NSManagedObjectID {
 
@@ -542,31 +692,86 @@ extension Internals {
                 }
                 self.reloadedItems.formUnion(newItemIDs)
             }
+            
+            mutating func unsafeUpdate<S: Sequence>(itemsAt indexPaths: S) where S.Element == IndexPath {
+                
+                var newItemIDs: Set<NSManagedObjectID> = []
+                for indexPath in indexPaths {
+
+                    self.sections[indexPath.section]
+                        .elements[indexPath.item].isReloaded = true
+                    newItemIDs.insert(self.unsafeItem(at: indexPath))
+                }
+                self.reloadedItems.formUnion(newItemIDs)
+            }
 
             mutating func append<C: Collection>(sectionIDs: C) where C.Element == String {
 
-                let newSections = sectionIDs.lazy.map({ Section(differenceIdentifier: $0) })
+                let sectionIndexTransformer = self.sectionIndexTransformer
+                let newSections = sectionIDs.lazy.map {
+                    
+                    return Section(
+                        differenceIdentifier: $0,
+                        indexTitle: sectionIndexTransformer($0)
+                    )
+                }
                 self.sections.append(contentsOf: newSections)
             }
 
-            mutating func insert<C: Collection>(sectionIDs: C, before beforeSectionID: String) where C.Element == String {
+            mutating func insert<C: Collection>(
+                sectionIDs: C,
+                before beforeSectionID: String
+            ) where C.Element == String {
 
                 guard let sectionIndex = self.sectionIndex(of: beforeSectionID) else {
 
                     Internals.abort("Section \"\(beforeSectionID)\" does not exist")
                 }
-                let newSections = sectionIDs.lazy.map({ Section(differenceIdentifier: $0) })
+                let sectionIndexTransformer = self.sectionIndexTransformer
+                let newSections = sectionIDs.lazy.map {
+                    
+                    return Section(
+                        differenceIdentifier: $0,
+                        indexTitle: sectionIndexTransformer($0)
+                    )
+                }
                 self.sections.insert(contentsOf: newSections, at: sectionIndex)
             }
 
-            mutating func insert<C: Collection>(sectionIDs: C, after afterSectionID: String) where C.Element == String {
+            mutating func insert<C: Collection>(
+                sectionIDs: C,
+                after afterSectionID: String
+            ) where C.Element == String {
 
                 guard let beforeIndex = self.sectionIndex(of: afterSectionID) else {
 
                     Internals.abort("Section \"\(afterSectionID)\" does not exist")
                 }
+                let sectionIndexTransformer = self.sectionIndexTransformer
                 let sectionIndex = self.sections.index(after: beforeIndex)
-                let newSections = sectionIDs.lazy.map({ Section(differenceIdentifier: $0) })
+                let newSections = sectionIDs.lazy.map {
+                    
+                    return Section(
+                        differenceIdentifier: $0,
+                        indexTitle: sectionIndexTransformer($0)
+                    )
+                }
+                self.sections.insert(contentsOf: newSections, at: sectionIndex)
+            }
+            
+            mutating func unsafeInsert<C: Collection>(
+                _ sectionIDs: C,
+                at sectionIndex: Int
+            ) where C.Element == String {
+                
+                let sectionIndexTransformer = self.sectionIndexTransformer
+                let newSections = sectionIDs.lazy.map {
+                    
+                    return Section(
+                        differenceIdentifier: $0,
+                        indexTitle: sectionIndexTransformer($0)
+                    )
+                }
                 self.sections.insert(contentsOf: newSections, at: sectionIndex)
             }
 
@@ -577,6 +782,16 @@ extension Internals {
                     self.remove(sectionID: sectionID)
                 }
             }
+            
+            mutating func unsafeRemove<S: Sequence>(
+                sectionsAt sectionIndices: S
+            ) where S.Element == Int {
+                
+                for sectionIndex in sectionIndices.sorted(by: >) {
+                    
+                    self.sections.remove(at: sectionIndex)
+                }
+            }
 
             mutating func move(sectionID: String, before beforeSectionID: String) {
 
@@ -604,8 +819,21 @@ extension Internals {
                 let sectionIndex = self.sections.index(after: beforeIndex)
                 self.sections.insert(removed, at: sectionIndex)
             }
+            
+            mutating func unsafeMove(
+                sectionAt sectionIndex: Int,
+                to newSectionIndex: Int
+            ) {
+                
+                self.sections.move(
+                    fromOffsets: .init(integer: sectionIndex),
+                    toOffset: newSectionIndex
+                )
+            }
 
-            mutating func update<S: Sequence>(sectionIDs: S) where S.Element == String {
+            mutating func update<S: Sequence>(
+                sectionIDs: S
+            ) where S.Element == String {
 
                 for sectionID in sectionIDs {
 
@@ -616,6 +844,16 @@ extension Internals {
                     self.sections[sectionIndex].isReloaded = true
                 }
             }
+            
+            mutating func unsafeUpdate<S: Sequence>(
+                sectionsAt sectionIndices: S
+            ) where S.Element == Int {
+                
+                for sectionIndex in sectionIndices {
+
+                    self.sections[sectionIndex].isReloaded = true
+                }
+            }
 
 
             // MARK: Private

Sources/Internals.DiffableDataUIDispatcher.swift

@@ -59,16 +59,14 @@ extension Internals {
                 Target,
                 StagedChangeset<[Internals.DiffableDataSourceSnapshot.Section]>,
                 @escaping ([Internals.DiffableDataSourceSnapshot.Section]) -> Void
-            ) -> Void,
-            completion: @escaping () -> Void
+            ) -> Void
         ) {
 
             self.apply(
                 .init(),
                 target: target,
                 animatingDifferences: animatingDifferences,
-                performUpdates: performUpdates,
-                completion: completion
+                performUpdates: performUpdates
             )
         }
         
@@ -80,8 +78,7 @@ extension Internals {
                 Target,
                 StagedChangeset<[Internals.DiffableDataSourceSnapshot.Section]>,
                 @escaping ([Internals.DiffableDataSourceSnapshot.Section]) -> Void
-            ) -> Void,
-            completion: @escaping () -> Void
+            ) -> Void
         ) {
             
             self.dispatcher.dispatch { [weak self] in
@@ -112,7 +109,6 @@ extension Internals {
                 #if canImport(QuartzCore)
 
                 CATransaction.begin()
-                CATransaction.setCompletionBlock(completion)
 
                 if !animatingDifferences {
 
@@ -122,11 +118,9 @@ extension Internals {
 
                 CATransaction.commit()
 
-
                 #else
 
                 performDiffingUpdates()
-                completion()
 
 
                 #endif
@@ -191,6 +185,20 @@ extension Internals {
             }
             return self.sections[section].elements.count
         }
+        
+        func sectionIndexTitle(for section: Int) -> String? {
+            
+            guard self.sections.indices.contains(section) else {
+
+                return nil
+            }
+            return self.sections[section].indexTitle
+        }
+        
+        func sectionIndexTitlesForAllSections() -> [String?] {
+            
+            return self.sections.map({ $0.indexTitle })
+        }
 
 
         // MARK: Private

Sources/Internals.FetchedDiffableDataSourceSnapshotDelegate.swift

@@ -41,9 +41,12 @@ import AppKit
 
 internal protocol FetchedDiffableDataSourceSnapshotHandler: AnyObject {
 
-    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: Internals.DiffableDataSourceSnapshot)
+    var sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String? { get }
     
-    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String?) -> String?
+    func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeContentWith snapshot: Internals.DiffableDataSourceSnapshot
+    )
 }
 
 
@@ -92,6 +95,7 @@ extension Internals {
 
             var snapshot = Internals.DiffableDataSourceSnapshot(
                 sections: controller.sections ?? [],
+                sectionIndexTransformer: self.handler.map({ $0.sectionIndexTransformer }) ?? { _ in nil },
                 fetchOffset: controller.fetchRequest.fetchOffset,
                 fetchLimit: controller.fetchRequest.fetchLimit
             )
@@ -109,10 +113,7 @@ extension Internals {
         @objc
         dynamic func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String) -> String? {
 
-            return self.handler?.controller(
-                controller,
-                sectionIndexTitleForSectionName: sectionName
-            )
+            return self.handler?.sectionIndexTransformer(sectionName)
         }
         
         @objc

Sources/Internals.FetchedResultsControllerDelegate.swift

@@ -29,18 +29,32 @@ import CoreData
 
 // MARK: - FetchedResultsControllerHandler
 
-@available(macOS 10.12, *)
 internal protocol FetchedResultsControllerHandler: AnyObject {
     
-    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeObject anObject: Any, atIndexPath indexPath: IndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: IndexPath?)
+    var sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String? { get }
     
-    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType)
+    func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeObject anObject: Any,
+        atIndexPath indexPath: IndexPath?,
+        forChangeType type: NSFetchedResultsChangeType,
+        newIndexPath: IndexPath?
+    )
     
-    func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
+    func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeSection sectionInfo: NSFetchedResultsSectionInfo,
+        atIndex sectionIndex: Int,
+        forChangeType type: NSFetchedResultsChangeType
+    )
     
-    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
+    func controllerWillChangeContent(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>
+    )
     
-    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String?) -> String?
+    func controllerDidChangeContent(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>
+    )
 }
 
 
@@ -50,7 +64,6 @@ extension Internals {
 
     // MARK: - FetchedResultsControllerDelegate
 
-    @available(macOS 10.12, *)
     internal final class FetchedResultsControllerDelegate: NSObject, NSFetchedResultsControllerDelegate {
 
         // MARK: Internal
@@ -90,14 +103,6 @@ extension Internals {
 
                 return
             }
-
-            if #available(iOS 10.3, tvOS 10.3, watchOS 3.2, macOS 10.13, *) {}
-            else {
-
-                self.deletedSections = []
-                self.insertedSections = []
-            }
-
             self.handler?.controllerWillChangeContent(controller)
         }
 
@@ -112,7 +117,6 @@ extension Internals {
 
                 return
             }
-
             self.handler?.controllerDidChangeContent(controller)
         }
 
@@ -123,102 +127,11 @@ extension Internals {
 
                 return
             }
-
-            if #available(iOS 10.3, tvOS 10.3, watchOS 3.2, macOS 10.13, *) {
-
-                self.handler?.controller(
-                    controller,
-                    didChangeObject: anObject,
-                    atIndexPath: indexPath,
-                    forChangeType: type,
-                    newIndexPath: newIndexPath
-                )
-                return
-            }
-
-            guard var actualType = NSFetchedResultsChangeType(rawValue: type.rawValue) else {
-
-                // This fix is for a bug where iOS passes 0 for NSFetchedResultsChangeType, but this is not a valid enum case.
-                // Swift will then always execute the first case of the switch causing strange behaviour.
-                // https://forums.developer.apple.com/thread/12184#31850
-                return
-            }
-
-            // This whole dance is a workaround for a nasty bug introduced in XCode 7 targeted at iOS 8 devices
-            // http://stackoverflow.com/questions/31383760/ios-9-attempt-to-delete-and-reload-the-same-index-path/31384014#31384014
-            // https://forums.developer.apple.com/message/9998#9998
-            // https://forums.developer.apple.com/message/31849#31849
-
-            if case .update = actualType,
-                indexPath != nil,
-                newIndexPath != nil {
-
-                actualType = .move
-            }
-
-            switch actualType {
-
-            case .update:
-                guard let section = indexPath?[0] else {
-
-                    return
-                }
-                if self.deletedSections.contains(section)
-                    || self.insertedSections.contains(section) {
-
-                    return
-                }
-
-            case .move:
-                guard let indexPath = indexPath, let newIndexPath = newIndexPath else {
-
-                    return
-                }
-                guard indexPath == newIndexPath else {
-
-                    break
-                }
-                if self.insertedSections.contains(indexPath[0]) {
-
-                    // Observers that handle the .Move change are advised to delete then reinsert the object instead of just moving. This is especially true when indexPath and newIndexPath are equal. For example, calling tableView.moveRowAtIndexPath(_:toIndexPath) when both indexPaths are the same will crash the tableView.
-                    self.handler?.controller(
-                        controller,
-                        didChangeObject: anObject,
-                        atIndexPath: indexPath,
-                        forChangeType: .move,
-                        newIndexPath: newIndexPath
-                    )
-                    return
-                }
-                if self.deletedSections.contains(indexPath[0]) {
-
-                    self.handler?.controller(
-                        controller,
-                        didChangeObject: anObject,
-                        atIndexPath: nil,
-                        forChangeType: .insert,
-                        newIndexPath: indexPath
-                    )
-                    return
-                }
-                self.handler?.controller(
-                    controller,
-                    didChangeObject: anObject,
-                    atIndexPath: indexPath,
-                    forChangeType: .update,
-                    newIndexPath: nil
-                )
-                return
-
-            default:
-                break
-            }
-
             self.handler?.controller(
                 controller,
                 didChangeObject: anObject,
                 atIndexPath: indexPath,
-                forChangeType: actualType,
+                forChangeType: type,
                 newIndexPath: newIndexPath
             )
         }
@@ -230,18 +143,6 @@ extension Internals {
 
                 return
             }
-
-            if #available(iOS 10.3, tvOS 10.3, watchOS 3.2, macOS 10.13, *) {}
-            else {
-
-                switch type {
-
-                case .delete:   self.deletedSections.insert(sectionIndex)
-                case .insert:   self.insertedSections.insert(sectionIndex)
-                default: break
-                }
-            }
-
             self.handler?.controller(
                 controller,
                 didChangeSection: sectionInfo,
@@ -253,19 +154,7 @@ extension Internals {
         @objc
         dynamic func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String) -> String? {
 
-            return self.handler?.controller(
-                controller,
-                sectionIndexTitleForSectionName: sectionName
-            )
+            return self.handler?.sectionIndexTransformer(sectionName)
         }
-
-
-        // MARK: Private
-
-        @nonobjc
-        private var deletedSections = Set<Int>()
-
-        @nonobjc
-        private var insertedSections = Set<Int>()
     }
 }

Sources/ListMonitor.swift

@@ -66,7 +66,6 @@ import CoreData
  ```
  In the example above, both `person1` and `person2` will contain the object at section=2, index=3.
  */
-@available(macOS 10.12, *)
 public final class ListMonitor<O: DynamicObject>: Hashable {
     
     // MARK: Public (Accessors)
@@ -394,19 +393,31 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
             observer,
             willChange: { (observer, monitor) in
                 
-                observer.listMonitorWillChange(monitor)
+                observer.listMonitorWillChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didChange: { (observer, monitor) in
                 
-                observer.listMonitorDidChange(monitor)
+                observer.listMonitorDidChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             willRefetch: { (observer, monitor) in
                 
-                observer.listMonitorWillRefetch(monitor)
+                observer.listMonitorWillRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didRefetch: { (observer, monitor) in
                 
-                observer.listMonitorDidRefetch(monitor)
+                observer.listMonitorDidRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
     }
@@ -429,38 +440,71 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
             observer,
             willChange: { (observer, monitor) in
                 
-                observer.listMonitorWillChange(monitor)
+                observer.listMonitorWillChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didChange: { (observer, monitor) in
                 
-                observer.listMonitorDidChange(monitor)
+                observer.listMonitorDidChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             willRefetch: { (observer, monitor) in
                 
-                observer.listMonitorWillRefetch(monitor)
+                observer.listMonitorWillRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didRefetch: { (observer, monitor) in
                 
-                observer.listMonitorDidRefetch(monitor)
+                observer.listMonitorDidRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
         self.registerObserver(
             observer,
             didInsertObject: { (observer, monitor, object, toIndexPath) in
                 
-                observer.listMonitor(monitor, didInsertObject: object, toIndexPath: toIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didInsertObject: object,
+                    toIndexPath: toIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didDeleteObject: { (observer, monitor, object, fromIndexPath) in
                 
-                observer.listMonitor(monitor, didDeleteObject: object, fromIndexPath: fromIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didDeleteObject: object,
+                    fromIndexPath: fromIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didUpdateObject: { (observer, monitor, object, atIndexPath) in
                 
-                observer.listMonitor(monitor, didUpdateObject: object, atIndexPath: atIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didUpdateObject: object,
+                    atIndexPath: atIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didMoveObject: { (observer, monitor, object, fromIndexPath, toIndexPath) in
                 
-                observer.listMonitor(monitor, didMoveObject: object, fromIndexPath: fromIndexPath, toIndexPath: toIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didMoveObject: object,
+                    fromIndexPath: fromIndexPath,
+                    toIndexPath: toIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
     }
@@ -483,49 +527,92 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
             observer,
             willChange: { (observer, monitor) in
                 
-                observer.listMonitorWillChange(monitor)
+                observer.listMonitorWillChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didChange: { (observer, monitor) in
                 
-                observer.listMonitorDidChange(monitor)
+                observer.listMonitorDidChange(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             willRefetch: { (observer, monitor) in
                 
-                observer.listMonitorWillRefetch(monitor)
+                observer.listMonitorWillRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didRefetch: { (observer, monitor) in
                 
-                observer.listMonitorDidRefetch(monitor)
+                observer.listMonitorDidRefetch(
+                    monitor,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
         self.registerObserver(
             observer,
             didInsertObject: { (observer, monitor, object, toIndexPath) in
                 
-                observer.listMonitor(monitor, didInsertObject: object, toIndexPath: toIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didInsertObject: object,
+                    toIndexPath: toIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didDeleteObject: { (observer, monitor, object, fromIndexPath) in
                 
-                observer.listMonitor(monitor, didDeleteObject: object, fromIndexPath: fromIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didDeleteObject: object,
+                    fromIndexPath: fromIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didUpdateObject: { (observer, monitor, object, atIndexPath) in
                 
-                observer.listMonitor(monitor, didUpdateObject: object, atIndexPath: atIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didUpdateObject: object,
+                    atIndexPath: atIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didMoveObject: { (observer, monitor, object, fromIndexPath, toIndexPath) in
                 
-                observer.listMonitor(monitor, didMoveObject: object, fromIndexPath: fromIndexPath, toIndexPath: toIndexPath)
+                observer.listMonitor(
+                    monitor,
+                    didMoveObject: object,
+                    fromIndexPath: fromIndexPath,
+                    toIndexPath: toIndexPath,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
         self.registerObserver(
             observer,
             didInsertSection: { (observer, monitor, sectionInfo, toIndex) in
                 
-                observer.listMonitor(monitor, didInsertSection: sectionInfo, toSectionIndex: toIndex)
+                observer.listMonitor(
+                    monitor,
+                    didInsertSection: sectionInfo,
+                    toSectionIndex: toIndex,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             },
             didDeleteSection: { (observer, monitor, sectionInfo, fromIndex) in
                 
-               observer.listMonitor(monitor, didDeleteSection: sectionInfo, fromSectionIndex: fromIndex)
+                observer.listMonitor(
+                    monitor,
+                    didDeleteSection: sectionInfo,
+                    fromSectionIndex: fromIndex,
+                    sourceIdentifier: monitor.fetchedResultsController.managedObjectContext.saveMetadata?.sourceIdentifier
+                )
             }
         )
     }
@@ -556,11 +643,18 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
      `refetch(...)` broadcasts `listMonitorWillRefetch(...)` to its observers immediately, and then `listMonitorDidRefetch(...)` after the new fetch request completes.
      
      - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - Important: Starting CoreStore 4.0, all `FetchClause`s required by the `ListMonitor` should be provided in the arguments list of `refetch(...)`.
      */
-    public func refetch(_ fetchClauses: FetchClause...) {
+    public func refetch(
+        _ fetchClauses: FetchClause...,
+        sourceIdentifier: Any?
+    ) {
         
-        self.refetch(fetchClauses)
+        self.refetch(
+            fetchClauses,
+            sourceIdentifier: sourceIdentifier
+        )
     }
     
     /**
@@ -569,14 +663,21 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
      `refetch(...)` broadcasts `listMonitorWillRefetch(...)` to its observers immediately, and then `listMonitorDidRefetch(...)` after the new fetch request completes.
      
      - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      - Important: Starting CoreStore 4.0, all `FetchClause`s required by the `ListMonitor` should be provided in the arguments list of `refetch(...)`.
      */
-    public func refetch(_ fetchClauses: [FetchClause]) {
+    public func refetch(
+        _ fetchClauses: [FetchClause],
+        sourceIdentifier: Any?
+    ) {
         
-        self.refetch { (fetchRequest) in
-            
-            fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-        }
+        self.refetch(
+            { (fetchRequest) in
+                
+                fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
+            },
+            sourceIdentifier: sourceIdentifier
+        )
     }
     
     
@@ -628,7 +729,12 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
     
     // MARK: Internal
     
-    internal convenience init(dataStack: DataStack, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
+    internal convenience init(
+        dataStack: DataStack,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) {
         
         self.init(
             context: dataStack.mainContext,
@@ -640,7 +746,13 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal convenience init(dataStack: DataStack, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (ListMonitor<O>) -> Void) {
+    internal convenience init(
+        dataStack: DataStack,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: @escaping (ListMonitor<O>) -> Void
+    ) {
         
         self.init(
             context: dataStack.mainContext,
@@ -652,7 +764,12 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
+    internal convenience init(
+        unsafeTransaction: UnsafeDataTransaction,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) {
         
         self.init(
             context: unsafeTransaction.context,
@@ -664,7 +781,13 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (ListMonitor<O>) -> Void) {
+    internal convenience init(
+        unsafeTransaction: UnsafeDataTransaction,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: @escaping (ListMonitor<O>) -> Void
+    ) {
         
         self.init(
             context: unsafeTransaction.context,
@@ -676,7 +799,12 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerChangeNotification(_ notificationKey: UnsafeRawPointer, name: Notification.Name, toObserver observer: AnyObject, callback: @escaping (_ monitor: ListMonitor<O>) -> Void) {
+    internal func registerChangeNotification(
+        _ notificationKey: UnsafeRawPointer,
+        name: Notification.Name,
+        toObserver observer: AnyObject,
+        callback: @escaping (_ monitor: ListMonitor<O>) -> Void
+    ) {
         
         Internals.setAssociatedRetainedObject(
             Internals.NotificationObserver(
@@ -696,7 +824,16 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerObjectNotification(_ notificationKey: UnsafeRawPointer, name: Notification.Name, toObserver observer: AnyObject, callback: @escaping (_ monitor: ListMonitor<O>, _ object: O, _ indexPath: IndexPath?, _ newIndexPath: IndexPath?) -> Void) {
+    internal func registerObjectNotification(
+        _ notificationKey: UnsafeRawPointer,
+        name: Notification.Name,
+        toObserver observer: AnyObject,
+        callback: @escaping (
+            _ monitor: ListMonitor<O>,
+            _ object: O,
+            _ indexPath: IndexPath?,
+            _ newIndexPath: IndexPath?
+        ) -> Void) {
         
         Internals.setAssociatedRetainedObject(
             Internals.NotificationObserver(
@@ -723,7 +860,16 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerSectionNotification(_ notificationKey: UnsafeRawPointer, name: Notification.Name, toObserver observer: AnyObject, callback: @escaping (_ monitor: ListMonitor<O>, _ sectionInfo: NSFetchedResultsSectionInfo, _ sectionIndex: Int) -> Void) {
+    internal func registerSectionNotification(
+        _ notificationKey: UnsafeRawPointer,
+        name: Notification.Name,
+        toObserver observer: AnyObject,
+        callback: @escaping (
+            _ monitor: ListMonitor<O>,
+            _ sectionInfo: NSFetchedResultsSectionInfo,
+            _ sectionIndex: Int
+        ) -> Void
+    ) {
         
         Internals.setAssociatedRetainedObject(
             Internals.NotificationObserver(
@@ -746,7 +892,24 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerObserver<U: AnyObject>(_ observer: U, willChange: @escaping (_ observer: U, _ monitor: ListMonitor<O>) -> Void, didChange: @escaping (_ observer: U, _ monitor: ListMonitor<O>) -> Void, willRefetch: @escaping (_ observer: U, _ monitor: ListMonitor<O>) -> Void, didRefetch: @escaping (_ observer: U, _ monitor: ListMonitor<O>) -> Void) {
+    internal func registerObserver<U: AnyObject>(
+        _ observer: U,
+        willChange: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>
+        ) -> Void,
+        didChange: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>
+        ) -> Void,
+        willRefetch: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>
+        ) -> Void,
+        didRefetch: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>
+        ) -> Void) {
         
         Internals.assert(
             Thread.isMainThread,
@@ -806,7 +969,33 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerObserver<U: AnyObject>(_ observer: U, didInsertObject: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ object: O, _ toIndexPath: IndexPath) -> Void, didDeleteObject: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ object: O, _ fromIndexPath: IndexPath) -> Void, didUpdateObject: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ object: O, _ atIndexPath: IndexPath) -> Void, didMoveObject: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ object: O, _ fromIndexPath: IndexPath, _ toIndexPath: IndexPath) -> Void) {
+    internal func registerObserver<U: AnyObject>(
+        _ observer: U,
+        didInsertObject: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ object: O, 
+            _ toIndexPath: IndexPath
+        ) -> Void,
+        didDeleteObject: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ object: O,
+            _ fromIndexPath: IndexPath
+        ) -> Void,
+        didUpdateObject: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ object: O,
+            _ atIndexPath: IndexPath
+        ) -> Void,
+        didMoveObject: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ object: O,
+            _ fromIndexPath: IndexPath,
+            _ toIndexPath: IndexPath
+        ) -> Void) {
         
         Internals.assert(
             Thread.isMainThread,
@@ -867,7 +1056,20 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         )
     }
     
-    internal func registerObserver<U: AnyObject>(_ observer: U, didInsertSection: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ sectionInfo: NSFetchedResultsSectionInfo, _ toIndex: Int) -> Void, didDeleteSection: @escaping (_ observer: U, _ monitor: ListMonitor<O>, _ sectionInfo: NSFetchedResultsSectionInfo, _ fromIndex: Int) -> Void) {
+    internal func registerObserver<U: AnyObject>(
+        _ observer: U,
+        didInsertSection: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ sectionInfo: NSFetchedResultsSectionInfo,
+            _ toIndex: Int
+        ) -> Void,
+        didDeleteSection: @escaping (
+            _ observer: U,
+            _ monitor: ListMonitor<O>,
+            _ sectionInfo: NSFetchedResultsSectionInfo,
+            _ fromIndex: Int
+        ) -> Void) {
         
         Internals.assert(
             Thread.isMainThread,
@@ -923,7 +1125,10 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         Internals.setAssociatedRetainedObject(nilValue, forKey: &self.didDeleteSectionKey, inObject: observer)
     }
     
-    internal func refetch(_ applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
+    internal func refetch(
+        _ applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        sourceIdentifier: Any?
+    ) {
         
         Internals.assert(
             Thread.isMainThread,
@@ -988,10 +1193,15 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
                     
                     self.isPendingRefetch = false
                     
+                    newFetchedResultsController.managedObjectContext.saveMetadata = .init(
+                        isSavingSynchronously: false,
+                        sourceIdentifier: sourceIdentifier
+                    )
                     NotificationCenter.default.post(
                         name: Notification.Name.listMonitorDidRefetchList,
                         object: self
                     )
+                    newFetchedResultsController.managedObjectContext.saveMetadata = nil
                 }
             }
         }
@@ -1008,7 +1218,7 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
     
     fileprivate var fetchedResultsController: Internals.CoreStoreFetchedResultsController
     fileprivate let taskGroup = DispatchGroup()
-    fileprivate let sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String?
+    internal let sectionByIndexTransformer: (_ sectionName: KeyPathString?) -> String?
     
     private let isSectioned: Bool
     
@@ -1052,7 +1262,15 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         }
     }
     
-    private static func recreateFetchedResultsController(context: NSManagedObjectContext, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) -> (controller: Internals.CoreStoreFetchedResultsController, delegate: Internals.FetchedResultsControllerDelegate) {
+    private static func recreateFetchedResultsController(
+        context: NSManagedObjectContext,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) -> (
+        controller: Internals.CoreStoreFetchedResultsController,
+        delegate: Internals.FetchedResultsControllerDelegate
+    ) {
         
         let fetchRequest = Internals.CoreStoreFetchRequest<NSManagedObject>()
         fetchRequest.fetchLimit = 0
@@ -1078,7 +1296,14 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
     private let from: From<O>
     private let sectionBy: SectionBy<O>?
     
-    private init(context: NSManagedObjectContext, transactionQueue: DispatchQueue, from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: ((ListMonitor<O>) -> Void)?) {
+    private init(
+        context: NSManagedObjectContext,
+        transactionQueue: DispatchQueue,
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: ((ListMonitor<O>) -> Void)?
+    ) {
         
         self.isSectioned = (sectionBy != nil)
         self.from = from
@@ -1092,11 +1317,11 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
         
         if let sectionIndexTransformer = sectionBy?.sectionIndexTransformer {
             
-            self.sectionIndexTransformer = sectionIndexTransformer
+            self.sectionByIndexTransformer = sectionIndexTransformer
         }
         else {
             
-            self.sectionIndexTransformer = { $0 }
+            self.sectionByIndexTransformer = { _ in nil }
         }
         self.transactionQueue = transactionQueue
         self.applyFetchClauses = applyFetchClauses
@@ -1125,7 +1350,7 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
                         
                         return
                 }
-                self.refetch(self.applyFetchClauses)
+                self.refetch(self.applyFetchClauses, sourceIdentifier: nil)
             }
         )
         
@@ -1149,7 +1374,7 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
                     
                     if previousStores != currentStores {
                         
-                        self.refetch(self.applyFetchClauses)
+                        self.refetch(self.applyFetchClauses, sourceIdentifier: nil)
                     }
                 }
                 
@@ -1178,7 +1403,6 @@ public final class ListMonitor<O: DynamicObject>: Hashable {
     
 // MARK: - ListMonitor where O: NSManagedObject
 
-@available(macOS 10.12, *)
 extension ListMonitor where O: NSManagedObject {
     
     /**
@@ -1236,7 +1460,6 @@ extension ListMonitor where O: NSManagedObject {
 
 // MARK: - ListMonitor where O: CoreStoreObject
 
-@available(macOS 10.12, *)
 extension ListMonitor where O: CoreStoreObject {
     
     /**
@@ -1279,7 +1502,7 @@ extension ListMonitor where O: CoreStoreObject {
     }
 
 
-    // MARK: - Deprecated
+    // MARK: Deprecated
 
     @available(*, deprecated, renamed: "O")
     public typealias D = O
@@ -1288,12 +1511,22 @@ extension ListMonitor where O: CoreStoreObject {
 
 // MARK: - ListMonitor: FetchedResultsControllerHandler
 
-@available(macOS 10.12, *)
 extension ListMonitor: FetchedResultsControllerHandler {
     
     // MARK: FetchedResultsControllerHandler
     
-    internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeObject anObject: Any, atIndexPath indexPath: IndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
+    internal var sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String? {
+        
+        return self.sectionByIndexTransformer
+    }
+    
+    internal func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeObject anObject: Any,
+        atIndexPath indexPath: IndexPath?,
+        forChangeType type: NSFetchedResultsChangeType,
+        newIndexPath: IndexPath?
+    ) {
         
         switch type {
             
@@ -1343,7 +1576,12 @@ extension ListMonitor: FetchedResultsControllerHandler {
         }
     }
     
-    internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
+    internal func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeSection sectionInfo: NSFetchedResultsSectionInfo,
+        atIndex sectionIndex: Int,
+        forChangeType type: NSFetchedResultsChangeType
+    ) {
         
         switch type {
             
@@ -1372,7 +1610,9 @@ extension ListMonitor: FetchedResultsControllerHandler {
         }
     }
     
-    internal func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
+    internal func controllerWillChangeContent(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>
+    ) {
         
         self.taskGroup.enter()
         NotificationCenter.default.post(
@@ -1381,7 +1621,9 @@ extension ListMonitor: FetchedResultsControllerHandler {
         )
     }
     
-   internal func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
+   internal func controllerDidChangeContent(
+    _ controller: NSFetchedResultsController<NSFetchRequestResult>
+   ) {
     
         defer {
             
@@ -1392,17 +1634,11 @@ extension ListMonitor: FetchedResultsControllerHandler {
             object: self
         )
     }
-    
-    internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String?) -> String? {
-    
-        return self.sectionIndexTransformer(sectionName)
-    }
 }
 
 
 // MARK: - Notification Keys
 
-@available(macOS 10.12, *)
 extension Notification.Name {
     
     fileprivate static let listMonitorWillChangeList = Notification.Name(rawValue: "listMonitorWillChangeList")

Sources/ListObserver.swift

@@ -39,7 +39,6 @@ import CoreData
  monitor.addObserver(self)
  ```
  */
-@available(macOS 10.12, *)
 public protocol ListObserver: AnyObject {
     
     /**
@@ -52,15 +51,54 @@ public protocol ListObserver: AnyObject {
      The default implementation does nothing.
      
      - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
      */
-    func listMonitorWillChange(_ monitor: ListMonitor<ListEntityType>)
+    func listMonitorWillChange(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    )
+    
+    /**
+     Handles processing just before a change to the observed list occurs. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     */
+    func listMonitorWillChange(
+        _ monitor: ListMonitor<ListEntityType>
+    )
+    
+    /**
+     Handles processing right after a change to the observed list occurs. (Required)
+     
+     - parameter monitor: the `ListMonitor` monitoring the object being observed
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitorDidChange(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    )
     
     /**
      Handles processing right after a change to the observed list occurs. (Required)
      
      - parameter monitor: the `ListMonitor` monitoring the object being observed
      */
-    func listMonitorDidChange(_ monitor: ListMonitor<ListEntityType>)
+    func listMonitorDidChange(
+        _ monitor: ListMonitor<ListEntityType>
+    )
+    
+    /**
+     This method is broadcast from within the `ListMonitor`'s `refetch(...)` method to let observers prepare for the internal `NSFetchedResultsController`'s pending change to its predicate, sort descriptors, etc. (Optional)
+     
+     - Important: All `ListMonitor` access between `listMonitorWillRefetch(_:)` and `listMonitorDidRefetch(_:)` will raise and assertion. The actual refetch will happen after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes.
+     - parameter monitor: the `ListMonitor` monitoring the object being observed
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitorWillRefetch(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    )
     
     /**
      This method is broadcast from within the `ListMonitor`'s `refetch(...)` method to let observers prepare for the internal `NSFetchedResultsController`'s pending change to its predicate, sort descriptors, etc. (Optional)
@@ -68,7 +106,21 @@ public protocol ListObserver: AnyObject {
      - Important: All `ListMonitor` access between `listMonitorWillRefetch(_:)` and `listMonitorDidRefetch(_:)` will raise and assertion. The actual refetch will happen after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes.
      - parameter monitor: the `ListMonitor` monitoring the object being observed
      */
-    func listMonitorWillRefetch(_ monitor: ListMonitor<ListEntityType>)
+    func listMonitorWillRefetch(
+        _ monitor: ListMonitor<ListEntityType>
+    )
+    
+    /**
+     After the `ListMonitor`'s `refetch(...)` method is called, this method is broadcast after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes. (Required)
+     
+     - Important: When `listMonitorDidRefetch(_:)` is called it should be assumed that all `ListMonitor`'s previous data have been reset, including counts, objects, and persistent stores.
+     - parameter monitor: the `ListMonitor` monitoring the object being observed
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitorDidRefetch(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    )
     
     /**
      After the `ListMonitor`'s `refetch(...)` method is called, this method is broadcast after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes. (Required)
@@ -76,18 +128,55 @@ public protocol ListObserver: AnyObject {
      - Important: When `listMonitorDidRefetch(_:)` is called it should be assumed that all `ListMonitor`'s previous data have been reset, including counts, objects, and persistent stores.
      - parameter monitor: the `ListMonitor` monitoring the object being observed
      */
-    func listMonitorDidRefetch(_ monitor: ListMonitor<ListEntityType>)
+    func listMonitorDidRefetch(
+        _ monitor: ListMonitor<ListEntityType>
+    )
 }
 
 
 // MARK: - ListObserver (Default Implementations)
 
-@available(macOS 10.12, *)
 extension ListObserver {
     
-    public func listMonitorWillChange(_ monitor: ListMonitor<ListEntityType>) { }
+    public func listMonitorWillChange(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitorWillChange(monitor)
+    }
     
-    public func listMonitorWillRefetch(_ monitor: ListMonitor<ListEntityType>) { }
+    public func listMonitorWillChange(
+        _ monitor: ListMonitor<ListEntityType>
+    ) {}
+    
+    public func listMonitorDidChange(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitorDidChange(monitor)
+    }
+    
+    public func listMonitorWillRefetch(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitorWillRefetch(monitor)
+    }
+    
+    public func listMonitorWillRefetch(
+        _ monitor: ListMonitor<ListEntityType>
+    ) {}
+    
+    public func listMonitorDidRefetch(
+        _ monitor: ListMonitor<ListEntityType>,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitorDidRefetch(monitor)
+    }
 }
 
 
@@ -103,7 +192,6 @@ extension ListObserver {
  monitor.addObserver(self)
  ```
  */
-@available(macOS 10.12, *)
 public protocol ListObjectObserver: ListObserver {
     
     /**
@@ -113,8 +201,44 @@ public protocol ListObjectObserver: ListObserver {
      - parameter monitor: the `ListMonitor` monitoring the list being observed
      - parameter object: the entity type for the inserted object
      - parameter indexPath: the new `NSIndexPath` for the inserted object
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didInsertObject object: ListEntityType, toIndexPath indexPath: IndexPath)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertObject object: ListEntityType,
+        toIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    )
+    
+    /**
+     Notifies that an object was inserted to the specified `NSIndexPath` in the list. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter object: the entity type for the inserted object
+     - parameter indexPath: the new `NSIndexPath` for the inserted object
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertObject object: ListEntityType,
+        toIndexPath indexPath: IndexPath
+    )
+    
+    /**
+     Notifies that an object was deleted from the specified `NSIndexPath` in the list. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter object: the entity type for the deleted object
+     - parameter indexPath: the `NSIndexPath` for the deleted object
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteObject object: ListEntityType,
+        fromIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    )
     
     /**
      Notifies that an object was deleted from the specified `NSIndexPath` in the list. (Optional)
@@ -124,7 +248,27 @@ public protocol ListObjectObserver: ListObserver {
      - parameter object: the entity type for the deleted object
      - parameter indexPath: the `NSIndexPath` for the deleted object
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didDeleteObject object: ListEntityType, fromIndexPath indexPath: IndexPath)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteObject object: ListEntityType,
+        fromIndexPath indexPath: IndexPath
+    )
+    
+    /**
+     Notifies that an object at the specified `NSIndexPath` was updated. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter object: the entity type for the updated object
+     - parameter indexPath: the `NSIndexPath` for the updated object
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didUpdateObject object: ListEntityType,
+        atIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    )
     
     /**
      Notifies that an object at the specified `NSIndexPath` was updated. (Optional)
@@ -134,7 +278,29 @@ public protocol ListObjectObserver: ListObserver {
      - parameter object: the entity type for the updated object
      - parameter indexPath: the `NSIndexPath` for the updated object
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didUpdateObject object: ListEntityType, atIndexPath indexPath: IndexPath)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didUpdateObject object: ListEntityType,
+        atIndexPath indexPath: IndexPath
+    )
+    
+    /**
+     Notifies that an object's index changed. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter object: the entity type for the moved object
+     - parameter fromIndexPath: the previous `NSIndexPath` for the moved object
+     - parameter toIndexPath: the new `NSIndexPath` for the moved object
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didMoveObject object: ListEntityType,
+        fromIndexPath: IndexPath,
+        toIndexPath: IndexPath,
+        sourceIdentifier: Any?
+    )
     
     /**
      Notifies that an object's index changed. (Optional)
@@ -145,22 +311,101 @@ public protocol ListObjectObserver: ListObserver {
      - parameter fromIndexPath: the previous `NSIndexPath` for the moved object
      - parameter toIndexPath: the new `NSIndexPath` for the moved object
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didMoveObject object: ListEntityType, fromIndexPath: IndexPath, toIndexPath: IndexPath)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didMoveObject object: ListEntityType,
+        fromIndexPath: IndexPath,
+        toIndexPath: IndexPath
+    )
 }
 
 
 // MARK: - ListObjectObserver (Default Implementations)
 
-@available(macOS 10.12, *)
 extension ListObjectObserver {
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didInsertObject object: ListEntityType, toIndexPath indexPath: IndexPath) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertObject object: ListEntityType,
+        toIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didInsertObject: object,
+            toIndexPath: indexPath
+        )
+    }
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didDeleteObject object: ListEntityType, fromIndexPath indexPath: IndexPath) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertObject object: ListEntityType,
+        toIndexPath indexPath: IndexPath
+    ) {}
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didUpdateObject object: ListEntityType, atIndexPath indexPath: IndexPath) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteObject object: ListEntityType,
+        fromIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didDeleteObject: object,
+            fromIndexPath: indexPath
+        )
+    }
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didMoveObject object: ListEntityType, fromIndexPath: IndexPath, toIndexPath: IndexPath) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteObject object: ListEntityType,
+        fromIndexPath indexPath: IndexPath
+    ) {}
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didUpdateObject object: ListEntityType,
+        atIndexPath indexPath: IndexPath,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didUpdateObject: object,
+            atIndexPath: indexPath
+        )
+    }
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didUpdateObject object: ListEntityType,
+        atIndexPath indexPath: IndexPath
+    ) {}
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didMoveObject object: ListEntityType,
+        fromIndexPath: IndexPath,
+        toIndexPath: IndexPath,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didMoveObject: object,
+            fromIndexPath: fromIndexPath,
+            toIndexPath: toIndexPath
+        )
+    }
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didMoveObject object: ListEntityType,
+        fromIndexPath: IndexPath,
+        toIndexPath: IndexPath
+    ) {}
 }
 
 
@@ -177,7 +422,6 @@ extension ListObjectObserver {
  monitor.addObserver(self)
  ```
  */
-@available(macOS 10.12, *)
 public protocol ListSectionObserver: ListObjectObserver {
     
     /**
@@ -187,8 +431,44 @@ public protocol ListSectionObserver: ListObjectObserver {
      - parameter monitor: the `ListMonitor` monitoring the list being observed
      - parameter sectionInfo: the `NSFetchedResultsSectionInfo` for the inserted section
      - parameter sectionIndex: the new section index for the new section
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didInsertSection sectionInfo: NSFetchedResultsSectionInfo, toSectionIndex sectionIndex: Int)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertSection sectionInfo: NSFetchedResultsSectionInfo,
+        toSectionIndex sectionIndex: Int,
+        sourceIdentifier: Any?
+    )
+    
+    /**
+     Notifies that a section was inserted at the specified index. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter sectionInfo: the `NSFetchedResultsSectionInfo` for the inserted section
+     - parameter sectionIndex: the new section index for the new section
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertSection sectionInfo: NSFetchedResultsSectionInfo,
+        toSectionIndex sectionIndex: Int
+    )
+    
+    /**
+     Notifies that a section was inserted at the specified index. (Optional)
+     The default implementation does nothing.
+     
+     - parameter monitor: the `ListMonitor` monitoring the list being observed
+     - parameter sectionInfo: the `NSFetchedResultsSectionInfo` for the deleted section
+     - parameter sectionIndex: the previous section index for the deleted section
+     - parameter sourceIdentifier: an optional identifier provided by the transaction source
+     */
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteSection sectionInfo: NSFetchedResultsSectionInfo,
+        fromSectionIndex sectionIndex: Int,
+        sourceIdentifier: Any?
+    )
     
     /**
      Notifies that a section was inserted at the specified index. (Optional)
@@ -198,16 +478,55 @@ public protocol ListSectionObserver: ListObjectObserver {
      - parameter sectionInfo: the `NSFetchedResultsSectionInfo` for the deleted section
      - parameter sectionIndex: the previous section index for the deleted section
      */
-    func listMonitor(_ monitor: ListMonitor<ListEntityType>, didDeleteSection sectionInfo: NSFetchedResultsSectionInfo, fromSectionIndex sectionIndex: Int)
+    func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteSection sectionInfo: NSFetchedResultsSectionInfo,
+        fromSectionIndex sectionIndex: Int
+    )
 }
 
 
 // MARK: - ListSectionObserver (Default Implementations)
 
-@available(macOS 10.12, *)
 extension ListSectionObserver {
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didInsertSection sectionInfo: NSFetchedResultsSectionInfo, toSectionIndex sectionIndex: Int) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertSection sectionInfo: NSFetchedResultsSectionInfo,
+        toSectionIndex sectionIndex: Int,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didInsertSection: sectionInfo,
+            toSectionIndex: sectionIndex
+        )
+    }
     
-    public func listMonitor(_ monitor: ListMonitor<ListEntityType>, didDeleteSection sectionInfo: NSFetchedResultsSectionInfo, fromSectionIndex sectionIndex: Int) { }
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didInsertSection sectionInfo: NSFetchedResultsSectionInfo,
+        toSectionIndex sectionIndex: Int
+    ) {}
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteSection sectionInfo: NSFetchedResultsSectionInfo,
+        fromSectionIndex sectionIndex: Int,
+        sourceIdentifier: Any?
+    ) {
+        
+        self.listMonitor(
+            monitor,
+            didDeleteSection: sectionInfo,
+            fromSectionIndex: sectionIndex
+        )
+    }
+    
+    public func listMonitor(
+        _ monitor: ListMonitor<ListEntityType>,
+        didDeleteSection sectionInfo: NSFetchedResultsSectionInfo,
+        fromSectionIndex sectionIndex: Int
+    ) {}
 }

Sources/ListPublisher+Reactive.swift

@@ -0,0 +1,109 @@
+//
+//  ListPublisher+Reactive.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine)
+
+import Combine
+
+
+// MARK: - ListPublisher
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ListPublisher {
+    
+    // MARK: Public
+    
+    /**
+     Combine utilities for the `ListPublisher` are exposed through this namespace
+     */
+    public var reactive: ListPublisher.ReactiveNamespace {
+        
+        return .init(self)
+    }
+    
+    
+    // MARK: - ReactiveNamespace
+    
+    /**
+     Combine utilities for the `ListPublisher` are exposed through this namespace. Extend this type if you need to add other Combine Publisher utilities for `ListPublisher`.
+     */
+    public struct ReactiveNamespace {
+        
+        // MARK: Public
+        
+        /**
+         The `ListPublisher` instance
+         */
+        public let base: ListPublisher
+        
+        
+        // MARK: Internal
+        
+        internal init(_ base: ListPublisher) {
+            
+            self.base = base
+        }
+    }
+}
+
+
+// MARK: - ListPublisher.ReactiveNamespace
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ListPublisher.ReactiveNamespace {
+
+    // MARK: Public
+    
+    /**
+     Returns a `Publisher` that emits a `ListSnapshot` whenever changes occur in the `ListPublisher`
+     ```
+     listPublisher.reactive
+         .snapshot(emitInitialValue: true)
+         .sink(
+             receiveCompletion: { result in
+                 // ...
+             },
+             receiveValue: { (listSnapshot) in
+                 dataSource.apply(
+                     listSnapshot,
+                     animatingDifferences: true
+                 )
+             }
+         )
+         .store(in: &cancellables)
+     ```
+     - parameter emitInitialValue: If `true`, the current value is immediately emitted to the first subscriber. If `false`, the event fires only starting the next `ListSnapshot` update.
+     - returns: A `Publisher` that emits a `ListSnapshot` whenever changes occur in the `ListPublisher`.
+     */
+    public func snapshot(emitInitialValue: Bool = true) -> ListPublisher.SnapshotPublisher {
+        
+        return .init(
+            listPublisher: self.base,
+            emitInitialValue: emitInitialValue
+        )
+    }
+}
+
+#endif

Sources/ListPublisher.SnapshotPublisher.swift

@@ -0,0 +1,163 @@
+//
+//  ListPublisher.SnapshotPublisher.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine)
+import Combine
+import CoreData
+
+
+// MARK: - ListPublisher
+
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+extension ListPublisher {
+    
+    // MARK: - SnapshotPublisher
+    
+    /**
+     A `Publisher` that emits a `ListSnapshot` whenever changes occur in the `ListPublisher`.
+     
+     - SeeAlso: ListPublisher.reactive.snapshot(emitInitialValue:)   
+     */
+    public struct SnapshotPublisher: Publisher {
+        
+        // MARK: Internal
+        
+        internal let listPublisher: ListPublisher<O>
+        internal let emitInitialValue: Bool
+        
+        
+        // MARK: Publisher
+        
+        public typealias Output = ListSnapshot<O>
+        public typealias Failure = Never
+        
+        public func receive<S: Subscriber>(subscriber: S) where S.Input == Output, S.Failure == Failure {
+            
+            subscriber.receive(
+                subscription: ListSnapshotSubscription(
+                    publisher: self.listPublisher,
+                    emitInitialValue: self.emitInitialValue,
+                    subscriber: subscriber
+                )
+            )
+        }
+        
+        
+        // MARK: - ListSnapshotSubscriber
+        
+        fileprivate final class ListSnapshotSubscriber: Subscriber {
+            
+            // MARK: Subscriber
+            
+            typealias Failure = Never
+            
+            func receive(subscription: Subscription) {
+                
+                subscription.request(.unlimited)
+            }
+            
+            func receive(_ input: Output) -> Subscribers.Demand {
+                
+                return .unlimited
+            }
+            
+            func receive(completion: Subscribers.Completion<Failure>) {}
+        }
+        
+        
+        // MARK: - ListSnapshotSubscription
+        
+        fileprivate final class ListSnapshotSubscription<S: Subscriber>: Subscription where S.Input == Output, S.Failure == Never {
+            
+            // MARK: FilePrivate
+            
+            init(
+                publisher: ListPublisher<O>,
+                emitInitialValue: Bool,
+                subscriber: S
+            ) {
+                
+                self.publisher = publisher
+                self.emitInitialValue = emitInitialValue
+                self.subscriber = subscriber
+            }
+            
+            
+            // MARK: Subscription
+            
+            func request(_ demand: Subscribers.Demand) {
+                
+                guard demand > 0 else {
+                    
+                    return
+                }
+                self.publisher.addObserver(
+                    self,
+                    notifyInitial: self.emitInitialValue,
+                    { [weak self] (publisher) in
+                        
+                        guard
+                            let self = self,
+                            let subscriber = self.subscriber
+                        else {
+                            
+                            return
+                        }
+                        _ = subscriber.receive(publisher.snapshot)
+                    }
+                )
+            }
+            
+            
+            // MARK: Cancellable
+            
+            func cancel() {
+                
+                self.subscriber = nil
+                
+                if Thread.isMainThread {
+                    
+                    self.publisher.removeObserver(self)
+                }
+                else {
+                    
+                    DispatchQueue.main.async {
+                        
+                        self.publisher.removeObserver(self)
+                    }
+                }
+            }
+            
+            
+            // MARK: Private
+            
+            private let publisher: ListPublisher<O>
+            private let emitInitialValue: Bool
+            private var subscriber: S?
+        }
+    }
+}
+
+#endif

Sources/ListPublisher.swift

@@ -25,16 +25,6 @@
 
 import CoreData
 
-#if canImport(Combine)
-import Combine
-
-#endif
-
-#if canImport(SwiftUI)
-import SwiftUI
-
-#endif
-
 
 // MARK: - ListPublisher
 
@@ -64,7 +54,6 @@ import SwiftUI
  ```
  All access to the `ListPublisher` items should be done via its `snapshot` value, which is a `struct` of type `ListSnapshot<O>`. `ListSnapshot`s are also designed to work well with `DiffableDataSource.TableViewAdapter`s and `DiffableDataSource.CollectionViewAdapter`s. For detailed examples, refer to the documentation for `DiffableDataSource.TableViewAdapter` and `DiffableDataSource.CollectionViewAdapter`.
  */
-@available(macOS 10.12, *)
 public final class ListPublisher<O: DynamicObject>: Hashable {
 
     // MARK: Public (Accessors)
@@ -87,18 +76,7 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
     /**
      A snapshot of the latest state of this list
      */
-    public fileprivate(set) var snapshot: ListSnapshot<O> = .init() {
-
-        willSet {
-
-            self.willChange()
-        }
-        didSet {
-
-            self.didChange()
-            self.notifyObservers()
-        }
-    }
+    public private(set) var snapshot: ListSnapshot<O> = .init()
 
 
     // MARK: Public (Observers)
@@ -127,7 +105,7 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
             "Attempted to add an observer of type \(Internals.typeName(observer)) outside the main thread."
         )
         self.observers.setObject(
-            Internals.Closure(callback),
+            Internals.Closure({ callback($0.listPublisher) }),
             forKey: observer
         )
         if notifyInitial {
@@ -135,6 +113,44 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
             callback(self)
         }
     }
+    
+    /**
+     Registers an object as an observer to be notified when changes to the `ListPublisher`'s snapshot occur.
+
+     To prevent retain-cycles, `ListPublisher` only keeps `weak` references to its observers.
+
+     For thread safety, this method needs to be called from the main thread. An assertion failure will occur (on debug builds only) if called from any thread other than the main thread.
+
+     Calling `addObserver(_:_:)` multiple times on the same observer is safe.
+
+     - parameter observer: an object to become owner of the specified `callback`
+     - parameter notifyInitial: if `true`, the callback is executed immediately with the current publisher state. Otherwise only succeeding updates will notify the observer. Default value is `false`.
+     - parameter initialSourceIdentifier: an optional value that identifies the initial callback invocation if `notifyInitial` is `true`.
+     - parameter callback: the closure to execute when changes occur
+     */
+    public func addObserver<T: AnyObject>(
+        _ observer: T,
+        notifyInitial: Bool = false,
+        initialSourceIdentifier: Any? = nil,
+        _ callback: @escaping (
+            _ listPublisher: ListPublisher<O>,
+            _ sourceIdentifier: Any?
+        ) -> Void
+    ) {
+
+        Internals.assert(
+            Thread.isMainThread,
+            "Attempted to add an observer of type \(Internals.typeName(observer)) outside the main thread."
+        )
+        self.observers.setObject(
+            Internals.Closure(callback),
+            forKey: observer
+        )
+        if notifyInitial {
+            
+            callback(self, initialSourceIdentifier)
+        }
+    }
 
     /**
      Unregisters an object from receiving notifications for changes to the `ListPublisher`'s snapshot.
@@ -165,8 +181,12 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      */
-    public func refetch<B: FetchChainableBuilderType>(_ clauseChain: B) throws where B.ObjectType == O {
+    public func refetch<B: FetchChainableBuilderType>(
+        _ clauseChain: B,
+        sourceIdentifier: Any? = nil
+    ) throws where B.ObjectType == O {
 
         try self.refetch(
             from: clauseChain.from,
@@ -174,7 +194,8 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
             applyFetchClauses: { (fetchRequest) in
 
                 clauseChain.fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-            }
+            },
+            sourceIdentifier: sourceIdentifier
         )
     }
 
@@ -189,8 +210,12 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
      )
      ```
      - parameter clauseChain: a `SectionMonitorBuilderType` built from a chain of clauses
+     - parameter sourceIdentifier: an optional value that identifies the source of this transaction. This identifier will be passed to the change notifications and callers can use it for custom handling that depends on the source.
      */
-    public func refetch<B: SectionMonitorBuilderType>(_ clauseChain: B) throws where B.ObjectType == O {
+    public func refetch<B: SectionMonitorBuilderType>(
+        _ clauseChain: B,
+        sourceIdentifier: Any? = nil
+    ) throws where B.ObjectType == O {
 
         try self.refetch(
             from: clauseChain.from,
@@ -198,9 +223,18 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
             applyFetchClauses: { (fetchRequest) in
 
                 clauseChain.fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
-            }
+            },
+            sourceIdentifier: sourceIdentifier
         )
     }
+    
+    /**
+     Used internally by CoreStore. Do not call directly.
+     */
+    public func cs_dataStack() -> DataStack? {
+        
+        return self.context.parentStack
+    }
 
 
     // MARK: Public (3rd Party Utilities)
@@ -235,8 +269,15 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
 
 
     // MARK: Internal
+    
+    internal private(set) lazy var context: NSManagedObjectContext = self.fetchedResultsController.managedObjectContext
 
-    internal convenience init(dataStack: DataStack, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
+    internal convenience init(
+        dataStack: DataStack,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) {
 
         self.init(
             context: dataStack.mainContext,
@@ -247,7 +288,13 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         )
     }
 
-    internal convenience init(dataStack: DataStack, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (ListPublisher<ObjectType>) -> Void) {
+    internal convenience init(
+        dataStack: DataStack,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: @escaping (ListPublisher<ObjectType>) -> Void
+    ) {
 
         self.init(
             context: dataStack.mainContext,
@@ -258,7 +305,12 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         )
     }
 
-    internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
+    internal convenience init(
+        unsafeTransaction: UnsafeDataTransaction,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) {
 
         self.init(
             context: unsafeTransaction.context,
@@ -269,7 +321,13 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         )
     }
 
-    internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (ListPublisher<ObjectType>) -> Void) {
+    internal convenience init(
+        unsafeTransaction: UnsafeDataTransaction,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: @escaping (ListPublisher<ObjectType>) -> Void
+    ) {
 
         self.init(
             context: unsafeTransaction.context,
@@ -280,7 +338,12 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         )
     }
 
-    internal func refetch(from: From<O>, sectionBy: SectionBy<O>?, applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) throws {
+    internal func refetch(
+        from: From<O>,
+        sectionBy: SectionBy<O>?,
+        applyFetchClauses: @escaping (_ fetchRequest:  Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        sourceIdentifier: Any?
+    ) throws {
 
         let (newFetchedResultsController, newFetchedResultsControllerDelegate) = Self.recreateFetchedResultsController(
             context: self.fetchedResultsController.managedObjectContext,
@@ -291,13 +354,19 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         self.query = (
             from: from,
             sectionBy: sectionBy,
-            sectionIndexTransformer: sectionBy?.sectionIndexTransformer ?? { $0 },
+            sectionIndexTransformer: sectionBy?.sectionIndexTransformer ?? { _ in nil },
             applyFetchClauses: applyFetchClauses
         )
         (self.fetchedResultsController, self.fetchedResultsControllerDelegate) = (newFetchedResultsController, newFetchedResultsControllerDelegate)
 
         newFetchedResultsControllerDelegate.handler = self
+        
+        newFetchedResultsController.managedObjectContext.saveMetadata = .init(
+            isSavingSynchronously: true,
+            sourceIdentifier: sourceIdentifier
+        )
         try newFetchedResultsController.performFetchFromSpecifiedStores()
+        newFetchedResultsController.managedObjectContext.saveMetadata = nil
     }
 
     deinit {
@@ -305,11 +374,20 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         self.fetchedResultsControllerDelegate.fetchedResultsController = nil
         self.observers.removeAllObjects()
     }
-
-
+    
+    
     // MARK: FilePrivate
+    
+    fileprivate typealias ObserverClosureType = Internals.Closure<(listPublisher: ListPublisher<O>, sourceIdentifier: Any?), Void>
+    
+    fileprivate func set(
+        snapshot: ListSnapshot<O>,
+        sourceIdentifier: Any?
+    )  {
 
-    fileprivate let rawObjectWillChange: Any?
+        self.snapshot = snapshot
+        self.notifyObservers(sourceIdentifier: sourceIdentifier)
+    }
     
     
     // MARK: Private
@@ -326,11 +404,17 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
     private var observerForWillChangePersistentStore: Internals.NotificationObserver!
     private var observerForDidChangePersistentStore: Internals.NotificationObserver!
 
-    private lazy var observers: NSMapTable<AnyObject, Internals.Closure<ListPublisher<O>, Void>> = .weakToStrongObjects()
+    private lazy var observers: NSMapTable<AnyObject, ObserverClosureType> = .weakToStrongObjects()
 
-    private lazy var context: NSManagedObjectContext = self.fetchedResultsController.managedObjectContext
-
-    private static func recreateFetchedResultsController(context: NSManagedObjectContext, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) -> (controller: Internals.CoreStoreFetchedResultsController, delegate: Internals.FetchedDiffableDataSourceSnapshotDelegate) {
+    private static func recreateFetchedResultsController(
+        context: NSManagedObjectContext,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
+    ) -> (
+        controller: Internals.CoreStoreFetchedResultsController,
+        delegate: Internals.FetchedDiffableDataSourceSnapshotDelegate
+    ) {
 
         let fetchRequest = Internals.CoreStoreFetchRequest<NSManagedObject>()
         fetchRequest.fetchLimit = 0
@@ -352,12 +436,18 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
         return (fetchedResultsController, fetchedResultsControllerDelegate)
     }
 
-    private init(context: NSManagedObjectContext, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: ((ListPublisher<ObjectType>) -> Void)?) {
+    private init(
+        context: NSManagedObjectContext,
+        from: From<ObjectType>,
+        sectionBy: SectionBy<ObjectType>?,
+        applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void,
+        createAsynchronously: ((ListPublisher<ObjectType>) -> Void)?
+    ) {
 
         self.query = (
             from: from,
             sectionBy: sectionBy,
-            sectionIndexTransformer: sectionBy?.sectionIndexTransformer ?? { $0 },
+            sectionIndexTransformer: sectionBy?.sectionIndexTransformer ?? { _ in nil },
             applyFetchClauses: applyFetchClauses
         )
         (self.fetchedResultsController, self.fetchedResultsControllerDelegate) = Self.recreateFetchedResultsController(
@@ -367,35 +457,24 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
             applyFetchClauses: applyFetchClauses
         )
 
-        if #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) {
-
-            #if canImport(Combine)
-            self.rawObjectWillChange = ObservableObjectPublisher()
-
-            #else
-            self.rawObjectWillChange = nil
-
-            #endif
-        }
-        else {
-
-            self.rawObjectWillChange = nil
-        }
-
         self.fetchedResultsControllerDelegate.handler = self
 
         try! self.fetchedResultsController.performFetchFromSpecifiedStores()
     }
 
-    private func notifyObservers() {
+    private func notifyObservers(sourceIdentifier: Any?) {
 
         guard let enumerator = self.observers.objectEnumerator() else {
 
             return
         }
+        let arguments: ObserverClosureType.Arguments = (
+            listPublisher: self,
+            sourceIdentifier: sourceIdentifier
+        )
         for closure in enumerator {
 
-            (closure as! Internals.Closure<ListPublisher<O>, Void>).invoke(with: self)
+            (closure as! ObserverClosureType).invoke(with: arguments)
         }
     }
 }
@@ -406,157 +485,24 @@ public final class ListPublisher<O: DynamicObject>: Hashable {
 extension ListPublisher: FetchedDiffableDataSourceSnapshotHandler {
 
     // MARK: FetchedDiffableDataSourceSnapshotHandler
+    
+    internal var sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String? {
+        
+        return self.query.sectionIndexTransformer
+    }
 
-    internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: Internals.DiffableDataSourceSnapshot) {
+    internal func controller(
+        _ controller: NSFetchedResultsController<NSFetchRequestResult>,
+        didChangeContentWith snapshot: Internals.DiffableDataSourceSnapshot
+    ) {
 
-        self.snapshot = .init(
-            diffableSnapshot: snapshot,
-            context: controller.managedObjectContext
+        let context = controller.managedObjectContext
+        self.set(
+            snapshot: .init(
+                diffableSnapshot: snapshot,
+                context: context
+            ),
+            sourceIdentifier: context.saveMetadata?.sourceIdentifier
         )
     }
-    
-    internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String?) -> String? {
-    
-        return self.query.sectionIndexTransformer(sectionName)
-    }
-}
-
-
-#if canImport(Combine)
-import Combine
-
-@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
-extension ListPublisher: ObservableObject {}
-
-@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
-extension ListPublisher: Publisher {
-    
-    // MARK: Publisher
-    
-    public typealias Output = ListSnapshot<O>
-    public typealias Failure = Never
-
-    public func receive<S: Subscriber>(subscriber: S) where S.Input == Output, S.Failure == Failure {
-        
-        subscriber.receive(
-            subscription: ListSnapshotSubscription(
-                publisher: self,
-                subscriber: subscriber
-            )
-        )
-    }
-    
-    
-    // MARK: - ListSnapshotSubscriber
-    
-    fileprivate final class ListSnapshotSubscriber: Subscriber {
-        
-        // MARK: Subscriber
-        
-        typealias Failure = Never
-        
-        func receive(subscription: Subscription) {
-            
-            subscription.request(.unlimited)
-        }
-        
-        func receive(_ input: Output) -> Subscribers.Demand {
-            
-            return .unlimited
-        }
-        
-        func receive(completion: Subscribers.Completion<Failure>) {}
-    }
-    
-    
-    // MARK: - ListSnapshotSubscription
-    
-    fileprivate final class ListSnapshotSubscription<S: Subscriber>: Subscription where S.Input == Output, S.Failure == Never {
-        
-        // MARK: FilePrivate
-        
-        init(publisher: ListPublisher<O>, subscriber: S) {
-            
-            self.publisher = publisher
-            self.subscriber = subscriber
-        }
-        
-        
-        // MARK: Subscription
-        
-        func request(_ demand: Subscribers.Demand) {
-            
-            guard demand > 0 else {
-                
-                return
-            }
-            self.publisher.addObserver(self) { [weak self] (publisher) in
-                
-                guard let self = self, let subscriber = self.subscriber else {
-                    
-                    return
-                }
-                _ = subscriber.receive(publisher.snapshot)
-            }
-        }
-        
-        
-        // MARK: Cancellable
-        
-        func cancel() {
-            self.publisher.removeObserver(self)
-            self.subscriber = nil
-        }
-        
-        
-        // MARK: Private
-        
-        private let publisher: ListPublisher<O>
-        private var subscriber: S?
-    }
-}
-
-#endif
-
-// MARK: - ListPublisher
-
-extension ListPublisher {
-
-    // MARK: ObservableObject
-
-    #if canImport(Combine)
-
-    @available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
-    public var objectWillChange: ObservableObjectPublisher {
-
-        return self.rawObjectWillChange! as! ObservableObjectPublisher
-    }
-
-    #endif
-
-    fileprivate func willChange() {
-
-        guard #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) else {
-
-            return
-        }
-        #if canImport(Combine)
-
-        #if canImport(SwiftUI)
-        withAnimation {
-
-            self.objectWillChange.send()
-        }
-
-        #endif
-
-        self.objectWillChange.send()
-
-        #endif
-    }
-
-    fileprivate func didChange() {
-
-        // nothing
-    }
 }

Sources/ListReader.swift

@@ -0,0 +1,123 @@
+//
+//  ListReader.swift
+//  CoreStore
+//
+//  Copyright © 2021 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Combine) && canImport(SwiftUI)
+
+import Combine
+import SwiftUI
+
+
+// MARK: - ListReader
+
+/**
+ A container view that reads list changes in a `ListPublisher`
+ */
+@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
+public struct ListReader<Object: DynamicObject, Content: View, Value>: View {
+    
+    // MARK: Internal
+    
+    /**
+     Creates an instance that creates views for `ListPublisher` changes.
+     ```
+     let people: ListPublisher<Person>
+     
+     var body: some View {
+     
+        List {
+            
+            ListReader(self.people) { listSnapshot in
+     
+                ForEach(objectIn: listSnapshot) { person in
+
+                    ProfileView(person)
+                }
+            }
+        }
+        .animation(.default)
+     }
+     ```
+     
+     - parameter listPublisher: The `ListPublisher` that the `ListReader` instance uses to create views dynamically
+     - parameter content: The view builder that receives an `ListSnapshot` instance and creates views dynamically.
+     */
+    public init(
+        _ listPublisher: ListPublisher<Object>,
+        @ViewBuilder content: @escaping (ListSnapshot<Object>) -> Content
+    ) where Value == ListSnapshot<Object> {
+        
+        self._list = .init(listPublisher)
+        self.content = content
+    }
+    
+    /**
+     Creates an instance that creates views for `ListPublisher` changes.
+     ```
+     let people: ListPublisher<Person>
+     
+     var body: some View {
+     
+         ListReader(self.people, keyPath: \.count) { count in
+
+             Text("Number of members: \(count)")
+         }
+     }
+     ```
+     
+     - parameter listPublisher: The `ListPublisher` that the `ListReader` instance uses to create views dynamically
+     - parameter keyPath: A `KeyPath` for a property in the `ListSnapshot` whose value will be sent to the views
+     - parameter content: The view builder that receives the value from the property `KeyPath` and creates views dynamically.
+     */
+    public init(
+        _ listPublisher: ListPublisher<Object>,
+        keyPath: KeyPath<ListSnapshot<Object>, Value>,
+        @ViewBuilder content: @escaping (Value) -> Content
+    ) {
+        
+        self._list = .init(listPublisher)
+        self.content = {
+            
+            content($0[keyPath: keyPath])
+        }
+    }
+    
+    
+    // MARK: View
+    
+    public var body: some View {
+        
+        self.content(self.list)
+    }
+    
+    
+    // MARK: Private
+    
+    @ListState
+    private var list: ListSnapshot<Object>
+    
+    private let content: (ListSnapshot<Object>) -> Content
+}
+
+#endif

Sources/ListSnapshot.SectionInfo.swift

@@ -0,0 +1,132 @@
+//
+//  ListSnapshot.SectionInfo.swift
+//  CoreStore
+//
+//  Copyright © 2018 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import CoreData
+
+
+// MARK: - ListSnapshot
+
+extension ListSnapshot {
+  
+    // MARK: - SectionInfo
+
+    public struct SectionInfo: Hashable, RandomAccessCollection {
+        
+        // MARK: Private
+        
+        public let sectionID: SectionID
+        
+        public let itemIDs: [ItemID]
+        
+        
+        // MARK: RandomAccessCollection
+        
+        public var startIndex: Index {
+            
+            return self.itemIDs.startIndex
+        }
+        
+        public var endIndex: Index {
+            
+            return self.itemIDs.endIndex
+        }
+
+        public func index(after i: Index) -> Index {
+
+            return self.itemIDs.index(after: i)
+        }
+
+        public func formIndex(after i: inout Index) {
+
+            self.itemIDs.formIndex(after: &i)
+        }
+
+        public func index(before i: Index) -> Index {
+
+            return self.itemIDs.index(before: i)
+        }
+
+        public func formIndex(before i: inout Index) {
+
+            self.itemIDs.formIndex(before: &i)
+        }
+
+
+        // MARK: BidirectionalCollection
+        
+        public subscript(position: Int) -> ObjectPublisher<O> {
+            
+            let itemID = self.itemIDs[position]
+            return self.context.objectPublisher(objectID: itemID)
+        }
+
+        public func index(_ i: Index, offsetBy distance: Int) -> Index {
+
+            return self.itemIDs.index(i, offsetBy: distance)
+        }
+
+        public func index(_ i: Index, offsetBy distance: Int, limitedBy limit: Int) -> Index? {
+
+            return self.itemIDs.index(i, offsetBy: distance, limitedBy: limit)
+        }
+
+        public func distance(from start: Index, to end: Index) -> Int {
+
+            return self.itemIDs.distance(from: start, to: end)
+        }
+
+        public subscript(bounds: Range<Index>) -> ArraySlice<Element> {
+
+            let itemIDs = self.itemIDs[bounds]
+            return ArraySlice(itemIDs.map(self.context.objectPublisher(objectID:)))
+        }
+
+        
+        // MARK: Sequence
+        
+        public typealias Element = ObjectPublisher<O>
+        
+        public typealias Index = Int
+        
+        
+        // MARK: Internal
+        
+        internal let context: NSManagedObjectContext
+        
+        internal init?(
+            sectionID: SectionID,
+            listSnapshot: ListSnapshot<O>
+        ) {
+            
+            guard let context = listSnapshot.context else {
+                
+                return nil
+            }
+            self.sectionID = sectionID
+            self.itemIDs = listSnapshot.itemIDs(inSectionWithID: sectionID)
+            self.context = context
+        }
+    }
+}

Sources/ListSnapshot.swift

@@ -100,7 +100,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIndex: the index for the object within the section. Using an `itemIndex` with an invalid range will raise an exception.
      - returns: the `ObjectPublisher<O>` interfacing the object at the specified section and item index
      */
-    public subscript(sectionIndex: Int, itemIndex: Int) -> ObjectPublisher<O> {
+    public subscript(
+        sectionIndex: Int,
+        itemIndex: Int
+    ) -> ObjectPublisher<O> {
 
         let context = self.context!
         let snapshot = self.diffableSnapshot
@@ -116,7 +119,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIndex: the index for the object within the section. Using an `itemIndex` with an invalid range will return `nil`.
      - returns: the `ObjectPublisher<O>` interfacing the object at the specified section and item index, or `nil` if out of bounds
      */
-    public subscript(safeSectionIndex sectionIndex: Int, safeItemIndex itemIndex: Int) -> ObjectPublisher<O>? {
+    public subscript(
+        safeSectionIndex sectionIndex: Int,
+        safeItemIndex itemIndex: Int
+    ) -> ObjectPublisher<O>? {
 
         guard let context = self.context else {
 
@@ -283,6 +289,29 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
 
         return self.diffableSnapshot.sectionIdentifier(containingItem: itemID)
     }
+    
+    /**
+     Returns an array of `SectionInfo` instances that contains a collection of `ObjectPublisher<O>` items for each section.
+     */
+    public func sections() -> [SectionInfo] {
+        
+        return self
+            .sectionIDs
+            .compactMap({ SectionInfo(sectionID: $0, listSnapshot: self) })
+    }
+    
+    /**
+     Returns the `SectionInfo` that the specified `ItemID` belongs to, or `nil` if it is not in the list.
+
+     - parameter itemID: the `ItemID`
+     - returns: the `SectionInfo` that the specified `ItemID` belongs to, or `nil` if it is not in the list
+     */
+    public func section(containingItemWithID itemID: ItemID) -> SectionInfo? {
+
+        return self
+            .sectionID(containingItemWithID: itemID)
+            .flatMap({ SectionInfo(sectionID: $0, listSnapshot: self) })
+    }
 
     /**
      All object identifiers in the `ListSnapshot`
@@ -310,7 +339,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter indices: the positions of the itemIDs to return. Specifying an invalid value will raise an exception.
      - returns: the `ItemID` array belonging to the given `SectionID` at the specified indices
      */
-    public func itemIDs<S: Sequence>(inSectionWithID sectionID: SectionID, atIndices indices: S) -> [ItemID] where S.Element == Int {
+    public func itemIDs<S: Sequence>(
+        inSectionWithID sectionID: SectionID,
+        atIndices indices: S
+    ) -> [ItemID] where S.Element == Int {
 
         let itemIDs = self.diffableSnapshot.itemIdentifiers(inSection: sectionID)
         return indices.map({ itemIDs[$0] })
@@ -375,7 +407,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIndices: the positions of items within the section. Specifying an invalid value will raise an exception.
      - returns: an array of `ObjectPublisher`s for the items in the specified `SectionID` and indices
      */
-    public func items<S: Sequence>(inSectionWithID sectionID: SectionID, atIndices itemIndices: S) -> [ObjectPublisher<O>] where S.Element == Int {
+    public func items<S: Sequence>(
+        inSectionWithID sectionID: SectionID,
+        atIndices itemIndices: S
+    ) -> [ObjectPublisher<O>] where S.Element == Int {
 
         let context = self.context!
         let itemIDs = self.diffableSnapshot.itemIdentifiers(inSection: sectionID)
@@ -423,7 +458,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIndices: the positions of items within the section. Specifying an invalid value will raise an exception.
      - returns: a lazy sequence of `ObjectPublisher`s for the items in the specified `SectionID` and indices
      */
-    public func lazy<S: Sequence>(inSectionWithID sectionID: SectionID, atIndices itemIndices: S) -> LazyMapSequence<S, ObjectPublisher<O>> where S.Element == Int {
+    public func lazy<S: Sequence>(
+        inSectionWithID sectionID: SectionID,
+        atIndices itemIndices: S
+    ) -> LazyMapSequence<S, ObjectPublisher<O>> where S.Element == Int {
 
         let context = self.context!
         let itemIDs = self.diffableSnapshot.itemIdentifiers(inSection: sectionID)
@@ -443,9 +481,32 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIDs: the object identifiers for the objects to append
      - parameter sectionID: the section to append the items to
      */
-    public mutating func appendItems<C: Collection>(withIDs itemIDs: C, toSectionWithID sectionID: SectionID? = nil) where C.Element == ItemID {
+    public mutating func appendItems<C: Collection>(
+        withIDs itemIDs: C,
+        toSectionWithID sectionID: SectionID? = nil
+    ) where C.Element == ItemID {
 
-        self.diffableSnapshot.appendItems(itemIDs, toSection: sectionID)
+        self.mutate {
+
+            $0.appendItems(itemIDs, toSection: sectionID)
+        }
+    }
+    
+    /**
+     Appends extra items to the specified section index
+
+     - parameter itemIDs: the object identifiers for the objects to append
+     - parameter sectionIndex: the section index to append the items to. Specifying an invalid value will raise an exception.
+     */
+    public mutating func appendItems<C: Collection>(
+        with itemIDs: C,
+        toSectionAt sectionIndex: Int
+    ) where C.Element == ItemID {
+
+        self.mutate {
+
+            $0.unsafeAppendItems(itemIDs, toSectionAt: sectionIndex)
+        }
     }
     
     /**
@@ -454,9 +515,15 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIDs: the object identifiers for the objects to insert
      - parameter beforeItemID: an existing identifier to insert items before of. Specifying an invalid value will raise an exception.
      */
-    public mutating func insertItems<C: Collection>(withIDs itemIDs: C, beforeItemID: ItemID) where C.Element == ItemID {
+    public mutating func insertItems<C: Collection>(
+        withIDs itemIDs: C,
+        beforeItemID: ItemID
+    ) where C.Element == ItemID {
 
-        self.diffableSnapshot.insertItems(itemIDs, beforeItem: beforeItemID)
+        self.mutate {
+
+            $0.insertItems(itemIDs, beforeItem: beforeItemID)
+        }
     }
     
     /**
@@ -465,9 +532,32 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemIDs: the object identifiers for the objects to insert
      - parameter beforeItemID: an existing identifier to insert items after of. Specifying an invalid value will raise an exception.
      */
-    public mutating func insertItems<C: Collection>(withIDs itemIDs: C, afterItemID: ItemID) where C.Element == ItemID {
+    public mutating func insertItems<C: Collection>(
+        withIDs itemIDs: C,
+        afterItemID: ItemID
+    ) where C.Element == ItemID {
 
-        self.diffableSnapshot.insertItems(itemIDs, afterItem: afterItemID)
+        self.mutate {
+
+            $0.insertItems(itemIDs, afterItem: afterItemID)
+        }
+    }
+    
+    /**
+     Inserts extra items at a specified index path
+
+     - parameter itemIDs: the object identifiers for the objects to insert
+     - parameter indexPath: an indexPath to insert the items into. Specifying an invalid value will raise an exception.
+     */
+    public mutating func insertItems<C: Collection>(
+        withIDs itemIDs: C,
+        at indexPath: IndexPath
+    ) where C.Element == ItemID {
+
+        self.mutate {
+
+            $0.unsafeInsertItems(itemIDs, at: indexPath)
+        }
     }
     
     /**
@@ -475,9 +565,25 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
 
      - parameter itemIDs: the object identifiers for the objects to delete
      */
-    public mutating func deleteItems<S: Sequence>(withIDs itemIDs: S) where S.Element == ItemID {
+    public mutating func deleteItems<C: Collection>(withIDs itemIDs: C) where C.Element == ItemID {
 
-        self.diffableSnapshot.deleteItems(itemIDs)
+        self.mutate {
+
+            $0.deleteItems(itemIDs)
+        }
+    }
+    
+    /**
+     Deletes the items at the specified index paths
+
+     - parameter itemIndexPaths: the index paths for the objects to delete. Specifying an invalid value will raise an exception.
+     */
+    public mutating func deleteItems<C: Collection>(at itemIndexPaths: C) where C.Element == IndexPath {
+
+        self.mutate {
+
+            $0.unsafeDeleteItems(at: itemIndexPaths)
+        }
     }
     
     /**
@@ -485,7 +591,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      */
     public mutating func deleteAllItems() {
 
-        self.diffableSnapshot.deleteAllItems()
+        self.mutate {
+
+            $0.deleteAllItems()
+        }
     }
     
     /**
@@ -494,9 +603,15 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemID: an object identifier in the list to move. Specifying an invalid value will raise an exception.
      - parameter beforeItemID: another identifier to move the item before of. Specifying an invalid value will raise an exception.
      */
-    public mutating func moveItem(withID itemID: ItemID, beforeItemID: ItemID) {
+    public mutating func moveItem(
+        withID itemID: ItemID,
+        beforeItemID: ItemID
+    ) {
 
-        self.diffableSnapshot.moveItem(itemID, beforeItem: beforeItemID)
+        self.mutate {
+
+            $0.moveItem(itemID, beforeItem: beforeItemID)
+        }
     }
     
     /**
@@ -505,9 +620,32 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter itemID: an object identifier in the list to move. Specifying an invalid value will raise an exception.
      - parameter beforeItemID: another identifier to move the item after of. Specifying an invalid value will raise an exception.
      */
-    public mutating func moveItem(withID itemID: ItemID, afterItemID: ItemID) {
+    public mutating func moveItem(
+        withID itemID: ItemID,
+        afterItemID: ItemID
+    ) {
 
-        self.diffableSnapshot.moveItem(itemID, afterItem: afterItemID)
+        self.mutate {
+
+            $0.moveItem(itemID, afterItem: afterItemID)
+        }
+    }
+    
+    /**
+     Moves an item at an index path to a new index path
+
+     - parameter itemIndexPath: an index path in the list to move. Specifying an invalid value will raise an exception.
+     - parameter newIndexPath: the new index path to move the item into. Specifying an invalid value will raise an exception.
+     */
+    public mutating func moveItem(
+        at itemIndexPath: IndexPath,
+        to newIndexPath: IndexPath
+    ) {
+
+        self.mutate {
+
+            $0.unsafeMoveItem(at: itemIndexPath, to: newIndexPath)
+        }
     }
     
     /**
@@ -515,9 +653,25 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
 
      - parameter itemIDs: the object identifiers to reload
      */
-    public mutating func reloadItems<S: Sequence>(withIDs itemIDs: S) where S.Element == ItemID {
+    public mutating func reloadItems<C: Collection>(withIDs itemIDs: C) where C.Element == ItemID {
 
-        self.diffableSnapshot.reloadItems(itemIDs)
+        self.mutate {
+
+            $0.reloadItems(itemIDs)
+        }
+    }
+    
+    /**
+     Marks the specified index paths as reloaded
+
+     - parameter itemIndexPaths: the index paths to reload. Specifying an invalid value will raise an exception.
+     */
+    public mutating func reloadItems<C: Collection>(at itemIndexPaths: C) where C.Element == IndexPath {
+
+        self.mutate {
+
+            $0.unsafeReloadItems(at: itemIndexPaths)
+        }
     }
     
     /**
@@ -527,7 +681,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      */
     public mutating func appendSections<C: Collection>(withIDs sectionIDs: C) where C.Element == SectionID {
 
-        self.diffableSnapshot.appendSections(sectionIDs)
+        self.mutate {
+
+            $0.appendSections(sectionIDs)
+        }
     }
     
     /**
@@ -536,9 +693,15 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter sectionIDs: the section identifiers for the sections to insert
      - parameter beforeSectionID: an existing identifier to insert items before of. Specifying an invalid value will raise an exception.
      */
-    public mutating func insertSections<C: Collection>(withIDs sectionIDs: C, beforeSectionID: SectionID) where C.Element == SectionID {
+    public mutating func insertSections<C: Collection>(
+        withIDs sectionIDs: C,
+        beforeSectionID: SectionID
+    ) where C.Element == SectionID {
 
-        self.diffableSnapshot.insertSections(sectionIDs, beforeSection: beforeSectionID)
+        self.mutate {
+
+            $0.insertSections(sectionIDs, beforeSection: beforeSectionID)
+        }
     }
     
     /**
@@ -547,9 +710,32 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter sectionIDs: the section identifiers for the sections to insert
      - parameter beforeSectionID: an existing identifier to insert items after of. Specifying an invalid value will raise an exception.
      */
-    public mutating func insertSections<C: Collection>(withIDs sectionIDs: C, afterSectionID: SectionID) where C.Element == SectionID {
+    public mutating func insertSections<C: Collection>(
+        withIDs sectionIDs: C,
+        afterSectionID: SectionID
+    ) where C.Element == SectionID {
 
-        self.diffableSnapshot.insertSections(sectionIDs, afterSection: afterSectionID)
+        self.mutate {
+
+            $0.insertSections(sectionIDs, afterSection: afterSectionID)
+        }
+    }
+    
+    /**
+     Inserts new sections into an existing section index
+
+     - parameter sectionIDs: the section identifiers for the sections to insert
+     - parameter sectionIndex: an existing section index to insert items into. Specifying an invalid value will raise an exception.
+     */
+    public mutating func insertSections<C: Collection>(
+        _ sectionIDs: C,
+        at sectionIndex: Int
+    ) where C.Element == String {
+
+        self.mutate {
+
+            $0.unsafeInsertSections(sectionIDs, at: sectionIndex)
+        }
     }
     
     /**
@@ -557,9 +743,25 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
 
      - parameter sectionIDs: the section identifiers for the sections to delete
      */
-    public mutating func deleteSections<S: Sequence>(withIDs sectionIDs: S) where S.Element == SectionID {
+    public mutating func deleteSections<C: Collection>(withIDs sectionIDs: C) where C.Element == SectionID {
 
-        self.diffableSnapshot.deleteSections(sectionIDs)
+        self.mutate {
+
+            $0.deleteSections(sectionIDs)
+        }
+    }
+    
+    /**
+     Deletes the specified section indices
+
+     - parameter sectionIndices: the section indices to delete. Specifying an invalid value will raise an exception.
+     */
+    public mutating func deleteSections<C: Collection>(at sectionIndices: C) where C.Element == Int {
+
+        self.mutate {
+
+            $0.unsafeDeleteSections(at: sectionIndices)
+        }
     }
     
     /**
@@ -568,9 +770,15 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter sectionID: a section identifier in the list to move. Specifying an invalid value will raise an exception.
      - parameter beforeSectionID: another identifier to move the section before of. Specifying an invalid value will raise an exception.
      */
-    public mutating func moveSection(withID sectionID: SectionID, beforeSectionID: SectionID) {
+    public mutating func moveSection(
+        withID sectionID: SectionID,
+        beforeSectionID: SectionID
+    ) {
 
-        self.diffableSnapshot.moveSection(sectionID, beforeSection: beforeSectionID)
+        self.mutate {
+
+            $0.moveSection(sectionID, beforeSection: beforeSectionID)
+        }
     }
     
     /**
@@ -579,9 +787,32 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
      - parameter sectionID: a section identifier in the list to move. Specifying an invalid value will raise an exception.
      - parameter afterSectionID: another identifier to move the section after of. Specifying an invalid value will raise an exception.
      */
-    public mutating func moveSection(withID sectionID: SectionID, afterSectionID: SectionID) {
+    public mutating func moveSection(
+        withID sectionID: SectionID,
+        afterSectionID: SectionID
+    ) {
 
-        self.diffableSnapshot.moveSection(sectionID, afterSection: afterSectionID)
+        self.mutate {
+
+            $0.moveSection(sectionID, afterSection: afterSectionID)
+        }
+    }
+    
+    /**
+     Moves a section at a specified index to a new index
+
+     - parameter sectionIndex: a section index in the list to move. Specifying an invalid value will raise an exception.
+     - parameter newSectionIndex: the new section index to move into. Specifying an invalid value will raise an exception.
+     */
+    public mutating func moveSection(
+        at sectionIndex: Int,
+        to newSectionIndex: Int
+    ) {
+
+        self.mutate {
+
+            $0.unsafeMoveSection(at: sectionIndex, to: newSectionIndex)
+        }
     }
     
     /**
@@ -589,9 +820,25 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
 
      - parameter sectionIDs: the section identifiers to reload
      */
-    public mutating func reloadSections<S: Sequence>(withIDs sectionIDs: S) where S.Element == SectionID {
+    public mutating func reloadSections<C: Collection>(withIDs sectionIDs: C) where C.Element == SectionID {
 
-        self.diffableSnapshot.reloadSections(sectionIDs)
+        self.mutate {
+
+            $0.reloadSections(sectionIDs)
+        }
+    }
+    
+    /**
+     Marks the specified section indices as reloaded
+
+     - parameter sectionIndices: the section indices to reload. Specifying an invalid value will raise an exception.
+     */
+    public mutating func reloadSections<C: Collection>(at sectionIndices: C) where C.Element == Int {
+
+        self.mutate {
+
+            $0.unsafeReloadSections(at: sectionIndices)
+        }
     }
 
 
@@ -673,21 +920,24 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
     // MARK: Equatable
     
     public static func == (_ lhs: Self, _ rhs: Self) -> Bool {
-        
-        return lhs.id == rhs.id
+
+        return lhs.context == rhs.context
+            && lhs.generation == rhs.generation
     }
     
     
     // MARK: Hashable
     
     public func hash(into hasher: inout Hasher) {
-        
-        hasher.combine(self.id)
+
+        hasher.combine(self.context)
+        hasher.combine(self.generation)
     }
     
     
     // MARK: Internal
     
+    internal let context: NSManagedObjectContext?
     internal private(set) var diffableSnapshot: Internals.DiffableDataSourceSnapshot
     
     internal init() {
@@ -696,7 +946,10 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
         self.context = nil
     }
     
-    internal init(diffableSnapshot: Internals.DiffableDataSourceSnapshot, context: NSManagedObjectContext) {
+    internal init(
+        diffableSnapshot: Internals.DiffableDataSourceSnapshot,
+        context: NSManagedObjectContext
+    ) {
 
         self.diffableSnapshot = diffableSnapshot
         self.context = context
@@ -705,7 +958,12 @@ public struct ListSnapshot<O: DynamicObject>: RandomAccessCollection, Hashable {
     
     // MARK: Private
     
-    private let id: UUID = .init()
-    private let context: NSManagedObjectContext?
+    private var generation: UUID = .init()
 
+    @inline(__always)
+    private mutating func mutate<T>(_ mutation: (inout Internals.DiffableDataSourceSnapshot) -> T) -> T {
+
+        self.generation = .init()
+        return mutation(&self.diffableSnapshot)
+    }
 }