WIP: CSImportableUniqueObject

Sources/ObjectiveC/CSImportableObject.swift

@@ -33,17 +33,25 @@ import CoreData
 public protocol CSImportableObject: class, AnyObject {
     
     /**
-     Return `true` if an object should be created from `source`. Return `false` to ignore and skip `source`. The default implementation returns `true`.
+     Return the expected class of the import source. If not implemented, transactions will not validate the import source's type.
+     
+     - returns: the expected class of the import source
+     */
+    @objc
+    optional static func classForImportSource() -> AnyClass
+    
+    /**
+     Return `YES` if an object should be created from `source`. Return `NO` to ignore and skip `source`. If not implemented, transactions assume `YES`.
      
      - parameter source: the object to import from
      - parameter transaction: the transaction that invoked the import. Use the transaction to fetch or create related objects if needed.
-     - returns: `true` if an object should be created from `source`. Return `false` to ignore.
+     - returns: `YES` if an object should be created from `source`. Return `NO` to ignore.
      */
     @objc
-    static func shouldInsertFromImportSource(source: AnyObject, inTransaction transaction: CSBaseDataTransaction) -> Bool
+    optional static func shouldInsertFromImportSource(source: AnyObject, inTransaction transaction: CSBaseDataTransaction) -> Bool
     
     /**
-     Implements the actual importing of data from `source`. Implementers should pull values from `source` and assign them to the receiver's attributes. Note that throwing from this method will cause subsequent imports that are part of the same `importObjects(:sourceArray:)` call to be cancelled.
+     Implements the actual importing of data from `source`. Implementers should pull values from `source` and assign them to the receiver's attributes. Note that throwing from this method will cause subsequent imports that are part of the same `-importObjects:sourceArray:` call to be cancelled.
      
      - parameter source: the object to import from
      - parameter transaction: the transaction that invoked the import. Use the transaction to fetch or create related objects if needed.

Sources/ObjectiveC/CSSaveResult.swift

@@ -36,7 +36,7 @@ import CoreData
 public final class CSSaveResult: NSObject, CoreStoreBridge {
     
     /**
-     `true` if the `commit` operation for the transaction succeeded, either because the save succeeded or because there were no changes to save. Returns `false` to indicate failure.
+     `YES` if the `commit` operation for the transaction succeeded, either because the save succeeded or because there were no changes to save. Returns `NO` to indicate failure.
      */
     @objc
     public var isSuccess: Bool {
@@ -45,7 +45,7 @@ public final class CSSaveResult: NSObject, CoreStoreBridge {
     }
     
     /**
-     `true` if the `commit` operation for the transaction failed, or `false` otherwise. When `true`, the `error` property returns the actual `NSError` for the failure.
+     `YES` if the `commit` operation for the transaction failed, or `NO` otherwise. When `YES`, the `error` property returns the actual `NSError` for the failure.
      */
     @objc
     public var isFailure: Bool {
@@ -54,7 +54,7 @@ public final class CSSaveResult: NSObject, CoreStoreBridge {
     }
     
     /**
-     `true` if the `commit` operation for the transaction succeeded and if there was an actual change made. Returns `false` otherwise.
+     `YES` if the `commit` operation for the transaction succeeded and if there was an actual change made. Returns `NO` otherwise.
      */
     @objc
     public var hasChanges: Bool {

Sources/ObjectiveC/CSUnsafeDataTransaction.swift

@@ -93,7 +93,7 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction {
     /**
      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 `true` to the argument. Without "undo" support, calling those methods will raise an exception.
+     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
@@ -109,7 +109,7 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction {
     /**
      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 `true`, 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.
+     - 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