Dart fixes

Author: alfonsogarciacaro

src/Fable.Transforms/Dart/Dart.fs

@@ -19,25 +19,64 @@ type AssignmentOperator =
     | AssignXorBitwise
     | AssignAndBitwise
 
+type TypeInfo =
+    {
+        IsRecord: bool
+        IsUnion: bool
+    }
+
 type Type =
     // Built in
-    | Integer
-    | Double
-    | Boolean
-    | String
-
     | Object
     | Dynamic
+
     | Void
     | MetaType
 
+    | Integer
+    | Double
+    | Boolean
+    | String
+
     | List of Type
     | Nullable of Type
 
     | Generic of name: string
-    | TypeReference of Ident * generics: Type list
+    | TypeReference of Ident * generics: Type list * info: TypeInfo
     | Function of argTypes: Type list * returnType: Type
 
+    static member reference(ident, ?generics, ?isRecord, ?isUnion) =
+        let info: TypeInfo = { IsRecord = defaultArg isRecord false; IsUnion = defaultArg isUnion false }
+        TypeReference(ident, defaultArg generics [], info)
+
+    static member needsCast (source: Type) (target: Type) =
+        match source, target with
+        | _, Object
+        | _, Dynamic -> false
+        | Void, Void
+        | MetaType, MetaType
+        | Integer, Integer
+        | Double, Double
+        | Boolean, Boolean
+        | String, String -> false
+
+        | List source, List target -> Type.needsCast source target
+        | Nullable source, Nullable target -> Type.needsCast source target
+        | source, Nullable target -> Type.needsCast source target
+        | Generic source, Generic target -> source <> target
+
+        // We should be able to detect class hierarchy here too
+        | TypeReference(sourceIdent, sourceGen, _),
+          TypeReference(targetIdent, targetGen, _) ->
+              not(
+                  sourceIdent.Name = targetIdent.Name
+                  && sourceIdent.ImportModule = targetIdent.ImportModule
+                  && sourceGen.Length = targetGen.Length
+                  && not(List.zip sourceGen targetGen |> List.exists (fun (s, t) -> Type.needsCast s t))
+              )
+
+        | _ -> true
+
 type Ident =
     { ImportModule: string option
       Name: string
@@ -206,7 +245,7 @@ type Statement =
     static member whileStatement(test, body) =
         WhileStatement(test, body)
     static member breakStatement(?label) =
-        BreakStatement(label)        
+        BreakStatement(label)
     static member continueStatement(?label) =
         ContinueStatement(label)
     static member tryStatement(body, ?handlers, ?finalizer) =
@@ -215,8 +254,9 @@ type Statement =
         addToScope ident.Name
         LocalVariableDeclaration(ident, kind, value)
     /// Variables that won't be added to scope
-    static member tempVariableDeclaration(ident: Ident, ?value) =
-        LocalVariableDeclaration(ident, Final, value)
+    static member tempVariableDeclaration(ident: Ident, ?isMutable, ?value) =
+        let isMutable = defaultArg isMutable false
+        LocalVariableDeclaration(ident, (if isMutable then Var else Final), value)
     static member functionDeclaration(name: string, args: FunctionArg list, body: Statement list, returnType: Type, ?genParams: GenericParam list) =
         LocalFunctionDeclaration {
             Name = name

src/Fable.Transforms/Dart/DartPrinter.fs

@@ -230,7 +230,7 @@ module PrinterExtensions =
                 printer.Print("?")
             | Generic name ->
                 printer.Print(name)
-            | TypeReference(ref, gen) ->
+            | TypeReference(ref, gen, _info) ->
                 printer.PrintIdent(ref)
                 printer.PrintList("<", ", ", ">", gen, printer.PrintType, skipIfEmpty=true)
             | Function(argTypes, returnType) ->
@@ -361,7 +361,7 @@ module PrinterExtensions =
             | Some p -> printer.Print(p + ".")
             printer.Print(ident.Name)
 
-        member printer.PrintIfStatment(test: Expression, consequent, alternate) =
+        member printer.PrintIfStatement(test: Expression, consequent, alternate) =
             printer.Print("if (")
             printer.Print(test)
             printer.Print(") ")
@@ -372,7 +372,7 @@ module PrinterExtensions =
                 match alternate with
                 | [IfStatement(test, consequent, alternate)] ->
                     printer.Print(" else ")
-                    printer.PrintIfStatment(test, consequent, alternate)
+                    printer.PrintIfStatement(test, consequent, alternate)
                 | alternate ->
                     // Get productive statements and skip `else` if they're empty
                     alternate
@@ -393,7 +393,7 @@ module PrinterExtensions =
                 printer.Print(statement)
 
             | IfStatement(test, consequent, alternate) ->
-                printer.PrintIfStatment(test, consequent, alternate)
+                printer.PrintIfStatement(test, consequent, alternate)
 
             | ForStatement(init, test, update, body) ->
                 printer.Print("for (")
@@ -626,7 +626,10 @@ module PrinterExtensions =
                     printer.PrintWithParensIfNotIdent(expr)
                 match op with
                 | UnaryMinus -> printUnaryOp "-" expr
-                | UnaryNot -> printUnaryOp "!" expr
+                | UnaryNot ->
+                    match expr with
+                    | UnaryExpression(UnaryNot, expr) -> printer.Print(expr)
+                    | _ -> printUnaryOp "!" expr
                 | UnaryNotBitwise -> printUnaryOp "~" expr
                 // TODO: I think Dart doesn't accept + prefix, check
                 | UnaryPlus
@@ -850,9 +853,12 @@ module PrinterExtensions =
 
             | Some value ->
                 let printType =
-                    // Nullable types usually need to be typed explicitly
+                    // Nullable types and unions usually need to be typed explicitly
+                    // Print type also if ident and expression types are different?
+                    // (this usually happens when removing unnecessary casts)
                     match ident.Type with
                     | Nullable _ -> true
+                    | TypeReference(_, _, info) -> info.IsUnion
                     | _ -> false
 
                 match kind, printType with