Add isNotEmpty, isNotBlank methods (#1396)

Adds convenience methods `isNotEmpty` and `isNotBlank`. This borrows the
same methods from Kotlin.

This helps users write more fluent constraints, for example,
`foo.isNotEmpty.implies(bar)`.

Adds:

* List#isNotEmpty
* Map#isNotEmpty
* Set#isNotEmpty
* Mapping#isNotEmpty
* Listing#isNotEmpty
* String#isNotEmpty
* String#isNotBlank

pkl-core/src/test/files/LanguageSnippetTests/input/api/list.pkl

@@ -12,6 +12,11 @@ facts {
     !list1.isEmpty
   }
 
+  ["isNotEmpty"] {
+    !List().isNotEmpty
+    list1.isNotEmpty
+  }
+
   ["every()"] {
     list1.every((x) -> x <= 3)
     !list1.every((x) -> x > 2)

pkl-core/src/test/files/LanguageSnippetTests/input/api/listing.pkl

@@ -42,7 +42,16 @@ facts {
     !altered.isEmpty
     !computedIndex.isEmpty
   }
-  
+
+  ["isNotEmpty"] {
+    !empty.isNotEmpty
+    !empty2.isNotEmpty
+    base.isNotEmpty
+    derived.isNotEmpty
+    altered.isNotEmpty
+    computedIndex.isNotEmpty
+  }
+
   ["lastIndex"] {
     empty.lastIndex == -1
     empty2.lastIndex == -1

pkl-core/src/test/files/LanguageSnippetTests/input/api/map.pkl

@@ -8,6 +8,11 @@ facts {
     !map1.isEmpty
   }
 
+  ["isNotEmpty"] {
+    !Map().isNotEmpty
+    map1.isNotEmpty
+  }
+
   ["containsKey()"] {
     map1.containsKey("two")
     !Map().containsKey("two")

pkl-core/src/test/files/LanguageSnippetTests/input/api/mapping.pkl

@@ -48,6 +48,13 @@ facts {
     empty2.isEmpty
   }
 
+  ["isNotEmpty"] {
+    base.isNotEmpty
+    derived.isNotEmpty
+    !empty.isNotEmpty
+    !empty2.isNotEmpty
+  }
+
   ["containsKey()"] {
     base.containsKey("Pigeon")
     base.containsKey("Parrot")

pkl-core/src/test/files/LanguageSnippetTests/input/api/set.pkl

@@ -12,6 +12,11 @@ facts {
     !set1.isEmpty
   }
 
+  ["isNotEmpty"] {
+    !Set().isNotEmpty
+    set1.isNotEmpty
+  }
+
   ["every()"] {
     set1.every((x) -> x <= 3)
     !set1.every((x) -> x > 2)

pkl-core/src/test/files/LanguageSnippetTests/input/api/string.pkl

@@ -11,6 +11,11 @@ facts {
     !str1.isEmpty
   }
 
+  ["isNotEmpty"] {
+    !"".isNotEmpty
+    str1.isNotEmpty
+  }
+
   ["isBlank"] {
     "".isBlank
     "   ".isBlank
@@ -18,6 +23,13 @@ facts {
     !str1.isBlank
   }
 
+  ["isNotBlank"] {
+    !"".isNotBlank
+    !"   ".isNotBlank
+    !"\t\n\r".isNotBlank
+    str1.isNotBlank
+  }
+
   ["isBase64"] {
     "".isBase64
     "AQIDBA==".isBase64

pkl-core/src/test/files/LanguageSnippetTests/output/api/list.pcf

@@ -3,6 +3,10 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+  }
   ["every()"] {
     true
     true

pkl-core/src/test/files/LanguageSnippetTests/output/api/listing.pcf

@@ -7,6 +7,14 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+    true
+    true
+    true
+    true
+  }
   ["lastIndex"] {
     true
     true

pkl-core/src/test/files/LanguageSnippetTests/output/api/map.pcf

@@ -3,6 +3,10 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+  }
   ["containsKey()"] {
     true
     true

pkl-core/src/test/files/LanguageSnippetTests/output/api/mapping.pcf

@@ -5,6 +5,12 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+    true
+    true
+  }
   ["containsKey()"] {
     true
     true

pkl-core/src/test/files/LanguageSnippetTests/output/api/reflectedDeclaration.pcf

@@ -830,6 +830,30 @@ alias {
           name = "isEmpty"
           allModifiers = Set()
           allAnnotations = List()
+        }, "isNotEmpty", new {
+          location {
+            line = XXXX
+            column = 3
+            displayUri = "https://github.com/apple/pkl/blob/$commitId/stdlib/base.pkl#LXXXX"
+          }
+          docComment = """
+            Tells whether this string is not empty.
+            
+            Facts:
+            ```
+            !"".isNotEmpty
+            "abc".isNotEmpty
+            ```
+            """
+          annotations = List(new {
+            version = "0.31.0"
+          })
+          modifiers = Set()
+          name = "isNotEmpty"
+          allModifiers = Set()
+          allAnnotations = List(new {
+            version = "0.31.0"
+          })
         }, "isBlank", new {
           location {
             line = XXXX
@@ -852,6 +876,32 @@ alias {
           name = "isBlank"
           allModifiers = Set()
           allAnnotations = List()
+        }, "isNotBlank", new {
+          location {
+            line = XXXX
+            column = 3
+            displayUri = "https://github.com/apple/pkl/blob/$commitId/stdlib/base.pkl#LXXXX"
+          }
+          docComment = """
+            Tells if at least one character is not Unicode "White_Space".
+            
+            Facts:
+            ```
+            !"".isNotBlank
+            !"   ".isNotBlank
+            "\\t\\n\\r".isNotBlank
+            "abc".isNotBlank
+            ```
+            """
+          annotations = List(new {
+            version = "0.31.0"
+          })
+          modifiers = Set()
+          name = "isNotBlank"
+          allModifiers = Set()
+          allAnnotations = List(new {
+            version = "0.31.0"
+          })
         }, "isRegex", new {
           location {
             line = XXXX
@@ -1124,6 +1174,30 @@ alias {
           name = "isEmpty"
           allModifiers = Set()
           allAnnotations = List()
+        }, "isNotEmpty", new {
+          location {
+            line = XXXX
+            column = 3
+            displayUri = "https://github.com/apple/pkl/blob/$commitId/stdlib/base.pkl#LXXXX"
+          }
+          docComment = """
+            Tells whether this string is not empty.
+            
+            Facts:
+            ```
+            !"".isNotEmpty
+            "abc".isNotEmpty
+            ```
+            """
+          annotations = List(new {
+            version = "0.31.0"
+          })
+          modifiers = Set()
+          name = "isNotEmpty"
+          allModifiers = Set()
+          allAnnotations = List(new {
+            version = "0.31.0"
+          })
         }, "isBlank", new {
           location {
             line = XXXX
@@ -1146,6 +1220,32 @@ alias {
           name = "isBlank"
           allModifiers = Set()
           allAnnotations = List()
+        }, "isNotBlank", new {
+          location {
+            line = XXXX
+            column = 3
+            displayUri = "https://github.com/apple/pkl/blob/$commitId/stdlib/base.pkl#LXXXX"
+          }
+          docComment = """
+            Tells if at least one character is not Unicode "White_Space".
+            
+            Facts:
+            ```
+            !"".isNotBlank
+            !"   ".isNotBlank
+            "\\t\\n\\r".isNotBlank
+            "abc".isNotBlank
+            ```
+            """
+          annotations = List(new {
+            version = "0.31.0"
+          })
+          modifiers = Set()
+          name = "isNotBlank"
+          allModifiers = Set()
+          allAnnotations = List(new {
+            version = "0.31.0"
+          })
         }, "isRegex", new {
           location {
             line = XXXX

pkl-core/src/test/files/LanguageSnippetTests/output/api/set.pcf

@@ -3,6 +3,10 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+  }
   ["every()"] {
     true
     true

pkl-core/src/test/files/LanguageSnippetTests/output/api/string.pcf

@@ -3,12 +3,22 @@ facts {
     true
     true
   }
+  ["isNotEmpty"] {
+    true
+    true
+  }
   ["isBlank"] {
     true
     true
     true
     true
   }
+  ["isNotBlank"] {
+    true
+    true
+    true
+    true
+  }
   ["isBase64"] {
     true
     true