Generate public initializers for Swift

.golden/kotlinDeprecatedFieldSpec/golden

@@ -1,5 +1,5 @@
 data class Data(
     val field0: Int,
-// Deprecated since build 500
-//    val field1: Int? = null,
+    // Deprecated since build 500
+    // val field1: Int? = null,
 )

.golden/swiftAdvancedNewtypeWithEnumFieldSpec/golden

@@ -1,3 +1,7 @@
 public struct Newtype {
     public var newtypeField: Enum
+
+    public init(newtypeField: Enum) {
+        self.newtypeField = newtypeField
+    }
 }

.golden/swiftAdvancedRecordSpec/golden

@@ -1,4 +1,9 @@
 public struct Data: CaseIterable, Hashable, Codable {
     public var field0: Int
     public var field1: Int?
+
+    public init(field0: Int, field1: Int? = nil) {
+        self.field0 = field0
+        self.field1 = field1
+    }
 }

.golden/swiftBasicDocSpec/golden

@@ -32,4 +32,9 @@ public struct Data {
     public var first: Int
     /// Second field, it's maybe an Int
     public var second: Int?
+
+    public init(first: Int, second: Int? = nil) {
+        self.first = first
+        self.second = second
+    }
 }

.golden/swiftBasicNewtypeWithConcreteFieldSpec/golden

@@ -1,3 +1,7 @@
 public struct Newtype {
     public var newtypeField: String
+
+    public init(newtypeField: String) {
+        self.newtypeField = newtypeField
+    }
 }

.golden/swiftBasicNewtypeWithEitherFieldSpec/golden

@@ -1,3 +1,7 @@
 public struct Newtype {
     public var newtypeField: Result<Int, String>
+
+    public init(newtypeField: Result<Int, String>) {
+        self.newtypeField = newtypeField
+    }
 }

.golden/swiftBasicRecordSpec/golden

@@ -1,4 +1,9 @@
 public struct Data {
     public var field0: Int
     public var field1: Int?
+
+    public init(field0: Int, field1: Int? = nil) {
+        self.field0 = field0
+        self.field1 = field1
+    }
 }

.golden/swiftDeprecatedFieldSpec/golden

@@ -2,4 +2,8 @@ public struct Data {
     public var field0: Int
     // Deprecated since build 500
     // public var field1: Int?
+
+    public init(field0: Int) {
+        self.field0 = field0
+    }
 }

.golden/swiftGenericStructSpec/golden

@@ -1,4 +1,9 @@
 public struct Tree<A: Hashable & Codable>: Hashable, Codable {
     public var rootLabel: A
     public var subForest: [Tree<A>]
+
+    public init(rootLabel: A, subForest: [Tree<A>]) {
+        self.rootLabel = rootLabel
+        self.subForest = subForest
+    }
 }

.golden/swiftMultipleTypeVariableSpec/golden

@@ -1,4 +1,9 @@
 public struct Data<A: Hashable & Codable, B: Hashable & Codable>: CaseIterable, Hashable, Codable {
     public var field0: A
     public var field1: B
+
+    public init(field0: A, field1: B) {
+        self.field0 = field0
+        self.field1 = field1
+    }
 }

.golden/swiftRecord0DuplicateRecordFieldSpec/golden

@@ -3,4 +3,9 @@ public struct Data0 {
     public var field0: Int
     /// not a duplicate
     public var field1: Int?
+
+    public init(field0: Int, field1: Int? = nil) {
+        self.field0 = field0
+        self.field1 = field1
+    }
 }

.golden/swiftRecord0SumOfProductDocSpec/golden

@@ -4,4 +4,9 @@ public struct Record0: CaseIterable, Hashable, Codable {
     public var record0Field0: Int
     /// The first field of record 0
     public var record0Field1: Int
+
+    public init(record0Field0: Int, record0Field1: Int) {
+        self.record0Field0 = record0Field0
+        self.record0Field1 = record0Field1
+    }
 }

.golden/swiftRecord0SumOfProductWithTaggedFlatObjectStyleSpec/golden

@@ -1,4 +1,9 @@
 public struct Record0: Codable {
     public var record0Field0: Int
     public var record0Field1: Int
+
+    public init(record0Field0: Int, record0Field1: Int) {
+        self.record0Field0 = record0Field0
+        self.record0Field1 = record0Field1
+    }
 }

.golden/swiftRecord0SumOfProductWithTaggedObjectStyleSpec/golden

@@ -1,4 +1,9 @@
 public struct Record0: Codable {
     public var record0Field0: Int
     public var record0Field1: Int
+
+    public init(record0Field0: Int, record0Field1: Int) {
+        self.record0Field0 = record0Field0
+        self.record0Field1 = record0Field1
+    }
 }

.golden/swiftRecord1DuplicateRecordFieldSpec/golden

@@ -3,4 +3,9 @@ public struct Data1 {
     public var field0: String
     /// not a duplicate
     public var field2: String?
+
+    public init(field0: String, field2: String? = nil) {
+        self.field0 = field0
+        self.field2 = field2
+    }
 }

.golden/swiftRecord1SumOfProductDocSpec/golden

@@ -4,4 +4,9 @@ public struct Record1: CaseIterable, Hashable, Codable {
     public var record1Field0: Int
     /// The first field of record 1
     public var record1Field1: Int
+
+    public init(record1Field0: Int, record1Field1: Int) {
+        self.record1Field0 = record1Field0
+        self.record1Field1 = record1Field1
+    }
 }

.golden/swiftRecord1SumOfProductWithTaggedFlatObjectStyleSpec/golden

@@ -1,4 +1,9 @@
 public struct Record1: Codable {
     public var record1Field0: Int
     public var record1Field1: Int
+
+    public init(record1Field0: Int, record1Field1: Int) {
+        self.record1Field0 = record1Field0
+        self.record1Field1 = record1Field1
+    }
 }

.golden/swiftRecord1SumOfProductWithTaggedObjectStyleSpec/golden

@@ -1,4 +1,9 @@
 public struct Record1: Codable {
     public var record1Field0: Int
     public var record1Field1: Int
+
+    public init(record1Field0: Int, record1Field1: Int) {
+        self.record1Field0 = record1Field0
+        self.record1Field1 = record1Field1
+    }
 }

.golden/swiftStrictFieldsCheck-RecordA/golden

@@ -1,3 +1,7 @@
 public struct RecordA {
     public var fieldA: String
+
+    public init(fieldA: String) {
+        self.fieldA = fieldA
+    }
 }

.golden/swiftStrictFieldsCheck-RecordB/golden

@@ -1,3 +1,7 @@
 public struct RecordB {
     public var c: String
+
+    public init(c: String) {
+        self.c = c
+    }
 }

.golden/swiftTypeVariableSpec/golden

@@ -1,3 +1,7 @@
 public struct Data<A: Hashable & Codable>: CaseIterable, Hashable, Codable {
     public var field0: A
+
+    public init(field0: A) {
+        self.field0 = field0
+    }
 }

src/Moat/Pretty/Kotlin.hs

@@ -71,8 +71,7 @@ prettyStructFields indents fields deprecatedFields = go fields
   where
     deprecatedFieldsMap = Map.fromList deprecatedFields
     prettyField (Field fieldName ty _) =
-      indents
-        ++ "val "
+      "val "
         ++ fieldName
         ++ ": "
         ++ prettyMoatType ty
@@ -84,11 +83,13 @@ prettyStructFields indents fields deprecatedFields = go fields
     go (field@(Field fieldName _ _) : fs) =
       case Map.lookup fieldName deprecatedFieldsMap of
         Just mComment ->
-          maybe "" (\comment -> "// " ++ comment ++ "\n") mComment
-            ++ "//"
+          indents
+            ++ maybe "" (\comment -> "// " ++ comment ++ "\n") mComment
+            ++ indents
+            ++ "// "
             ++ prettyField field
             ++ go fs
-        Nothing -> prettyField field ++ go fs
+        Nothing -> indents ++ prettyField field ++ go fs
 
 prettyEnumCases :: String -> [EnumCase] -> String
 prettyEnumCases indents = go

src/Moat/Pretty/Swift.hs

@@ -54,6 +54,7 @@ prettySwiftDataWith indent = \case
       ++ " {"
       ++ newlineNonEmpty structFields
       ++ prettyStructFields indents structFields structDeprecatedFields
+      ++ prettyStructInitializer indents structFields structDeprecatedFields
       ++ newlineNonEmpty structPrivateTypes
       ++ prettyPrivateTypes indents structPrivateTypes
       ++ prettyTags indents structTags
@@ -287,6 +288,35 @@ prettyStructFields indents fields deprecatedFields = go fields
             ++ prettyField field
             ++ go fs
 
+prettyStructInitializer :: String -> [Field] -> [(String, Maybe String)] -> String
+prettyStructInitializer indents fields deprecatedFields =
+  case activeFields of
+    [] -> "" -- No initializer needed if there are no active fields
+    _ ->
+      "\n"
+        ++ indents
+        ++ "public init("
+        ++ intercalate ", " (map prettyParam activeFields)
+        ++ ") {\n"
+        ++ concatMap (prettyAssignment indents) activeFields
+        ++ indents
+        ++ "}\n"
+  where
+    deprecatedFieldNames = map fst deprecatedFields
+    activeFields = filter (\(Field name _ _) -> name `notElem` deprecatedFieldNames) fields
+
+    isOptional :: MoatType -> Bool
+    isOptional (Optional _) = True
+    isOptional _ = False
+
+    prettyParam :: Field -> String
+    prettyParam (Field fieldName fieldType _) =
+      fieldName ++ ": " ++ prettyMoatType fieldType ++ (if isOptional fieldType then " = nil" else "")
+
+    prettyAssignment :: String -> Field -> String
+    prettyAssignment indentStr (Field fieldName _ _) =
+      indentStr ++ "    self." ++ fieldName ++ " = " ++ fieldName ++ "\n"
+
 prettyNewtypeField :: String -> Field -> String -> String
 prettyNewtypeField indents (Field alias fieldType _) fieldName =
   indents

test/DeprecatedFieldSpec.hs

@@ -24,7 +24,7 @@ mobileGenWith
 
 spec :: Spec
 spec =
-  fdescribe "stays golden" $ do
+  describe "stays golden" $ do
     let moduleName = "DeprecatedFieldSpec"
     it "swift" $
       defaultGolden ("swift" <> moduleName) (showSwift @Data)