feat(transpiler): constructor and typed field semantics

fixes #11 (constructor and typed field semantics)
fixes #42 (Should we infer class property types from ctor args ?)
fixes #17 (number (js) should map to num (dart))

Closes #45

modules/change_detection/src/change_detection.js

@@ -12,7 +12,7 @@ export class ChangeDetection {
   }
 
   detectChanges():int {
-    var current:Record = _rootWatchGroup._headRecord;
+    var current:Record = _rootWatchGroup.headRecord;
     var count:number = 0;
     while (current != null) {
       if (current.check()) {

modules/change_detection/src/watch_group.js

@@ -2,11 +2,11 @@ import {ProtoRecord, Record} from './record';
 import {FIELD} from 'facade/lang';
 
 export class ProtoWatchGroup {
-  @FIELD('final _headRecord:ProtoRecord')
-  @FIELD('final _tailRecord:ProtoRecord')
+  @FIELD('final headRecord:ProtoRecord')
+  @FIELD('final tailRecord:ProtoRecord')
   constructor() {
-    this._headRecord = null;
-    this._tailRecord = null;
+    this.headRecord = null;
+    this.tailRecord = null;
   }
 
   /**
@@ -29,7 +29,7 @@ export class ProtoWatchGroup {
     var watchGroup:WatchGroup = new WatchGroup(this, dispatcher);
     var head:Record = null;
     var tail:Record = null;
-    var proto:ProtoRecord = this._headRecord;
+    var proto:ProtoRecord = this.headRecord;
 
     while(proto != null) {
       tail = proto.instantiate(watchGroup);
@@ -37,14 +37,14 @@ export class ProtoWatchGroup {
       proto = proto.next;
     }
 
-    proto = this._headRecord;
+    proto = this.headRecord;
     while(proto != null) {
       proto.instantiateComplete();
       proto = proto.next;
     }
 
-    watchGroup._headRecord = head;
-    watchGroup._tailRecord = tail;
+    watchGroup.headRecord = head;
+    watchGroup.tailRecord = tail;
     return watchGroup;
   }
 
@@ -53,13 +53,13 @@ export class ProtoWatchGroup {
 export class WatchGroup {
   @FIELD('final protoWatchGroup:ProtoWatchGroup')
   @FIELD('final dispatcher:WatchGroupDispatcher')
-  @FIELD('final _headRecord:Record')
-  @FIELD('final _tailRecord:Record')
+  @FIELD('final headRecord:Record')
+  @FIELD('final tailRecord:Record')
   constructor(protoWatchGroup:ProtoWatchGroup, dispatcher:WatchGroupDispatcher) {
     this.protoWatchGroup = protoWatchGroup;
     this.dispatcher = dispatcher;
-    this._headRecord = null;
-    this._tailRecord = null;
+    this.headRecord = null;
+    this.tailRecord = null;
   }
 
   insertChildGroup(newChild:WatchGroup, insertAfter:WatchGroup) {

tools/transpiler/spec/classes_spec.js

@@ -1,4 +1,5 @@
 import {describe, it, expect} from 'test_lib/test_lib';
+import {CONST} from './fixtures/annotations';
 
 // Constructor
 // Define fields
@@ -13,6 +14,28 @@ class Foo {
   }
 }
 
+class SubFoo extends Foo {
+  constructor(a, b) {
+    this.c = 3;
+    super(a, b);
+  }
+}
+
+class Const {
+  @CONST
+  constructor(a:number) {
+    this.a = a;
+  }
+}
+
+class SubConst extends Const {
+  @CONST
+  constructor(a:number, b:number) {
+    super(a);
+    this.b = b;
+  }
+}
+
 export function main() {
   describe('classes', function() {
     it('should work', function() {
@@ -22,5 +45,21 @@ export function main() {
       expect(foo.b).toBe(3);
       expect(foo.sum()).toBe(5);
     });
+
+    it('@CONST should be transpiled to a const constructor', function() {
+      var subConst = new SubConst(1, 2);
+      expect(subConst.a).toBe(1);
+      expect(subConst.b).toBe(2);
+    });
+
+    describe('inheritance', function() {
+      it('should support super call', function () {
+        var subFoo = new SubFoo(1, 2);
+        expect(subFoo.a).toBe(1);
+        expect(subFoo.b).toBe(2);
+        expect(subFoo.c).toBe(3);
+      });
+    });
   });
+
 }

tools/transpiler/spec/fixtures/annotations.dart

@@ -11,6 +11,10 @@ class Provide {
   const Provide(this.token);
 }
 
+class CONST {
+  const CONST();
+}
+
 // TODO: this api does not yet return an array as we don't have
 // a nice array wrapper for Dart
 readFirstAnnotation(clazz) {

tools/transpiler/spec/fixtures/annotations.es6

@@ -10,6 +10,8 @@ export class Provide {
   }
 }
 
+export class CONST {
+}
 
 // TODO: this api does not yet return an array as we don't have
 // a nice array wrapper for Dart

tools/transpiler/src/ast/class_field.js

@@ -1,20 +0,0 @@
-import {ParseTree} from 'traceur/src/syntax/trees/ParseTree';
-
-var CLASS_FIELD = 'CLASS_FIELD';
-
-export class ClassFieldParseTree extends ParseTree {
-  constructor(location, identifier, typeAnnotation) {
-    this.location = location;
-    this.identifier = identifier;
-    this.typeAnnotation = typeAnnotation;
-  }
-  get type() {
-    return CLASS_FIELD;
-  }
-  visit(visitor) {
-    visitor.visitClassField(this);
-  }
-  transform(transformer) {
-    return this;
-  }
-}

tools/transpiler/src/codegeneration/ClassTransformer.js

@@ -1,25 +1,44 @@
-import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+import {ParseTreeTransformer} from './ParseTreeTransformer';
 
 import {
-  PROPERTY_METHOD_ASSIGNMENT,
+  BINARY_EXPRESSION,
+  CALL_EXPRESSION,
+  IDENTIFIER_EXPRESSION,
   MEMBER_EXPRESSION,
-  THIS_EXPRESSION,
-  BINARY_EXPRESSION
+  PROPERTY_METHOD_ASSIGNMENT,
+  SUPER_EXPRESSION,
+  THIS_EXPRESSION
 } from 'traceur/src/syntax/trees/ParseTreeType';
 
+import {EQUAL} from 'traceur/src/syntax/TokenType';
+
 import {CONSTRUCTOR} from 'traceur/src/syntax/PredefinedName';
 
 import {propName} from 'traceur/src/staticsemantics/PropName';
 
-import {ClassFieldParseTree} from '../ast/class_field';
+import {
+  BinaryExpression,
+  BindingIdentifier,
+  IdentifierExpression
+} from 'traceur/src/syntax/trees/ParseTrees';
+
+import {
+  ClassFieldDeclaration,
+  PropertyConstructorAssignment
+} from '../syntax/trees/ParseTrees';
 
 /**
  * Transforms class declaration:
- * - rename constructor (name of the class - default Dart constructor)
- *
+ * - rename constructor to the name of the class (default Dart constructor),
+ * - class fields are extracted from `this.field = expression;` in the ctor body,
+ * - `@CONST` annotations on the ctor result in a const constructor & final fields in Dart,
+ * - const constructor body is converted to an initializerList
  */
-
 export class ClassTransformer extends ParseTreeTransformer {
+  constructor(idGenerator, reporter) {
+    this.reporter_ = reporter;
+  }
+
   /**
    * @param {ClassDeclaration} tree
    * @returns {ParseTree}
@@ -28,12 +47,17 @@ export class ClassTransformer extends ParseTreeTransformer {
     var className = tree.name.identifierToken.toString();
     var argumentTypesMap = {};
     var fields = [];
+    var isConst;
+    var that = this;
 
-    tree.elements.forEach(function(elementTree) {
+    tree.elements.forEach(function(elementTree, index) {
       if (elementTree.type === PROPERTY_METHOD_ASSIGNMENT &&
           !elementTree.isStatic &&
           propName(elementTree) === CONSTRUCTOR) {
 
+        isConst = elementTree.annotations.some((annotation) =>
+          annotation.name.identifierToken.value === 'CONST');
+
         // Store constructor argument types,
         // so that we can use them to set the types of simple-assigned fields.
         elementTree.parameterList.parameters.forEach(function(p) {
@@ -48,15 +72,54 @@ export class ClassTransformer extends ParseTreeTransformer {
 
         // Collect all fields, defined in the constructor.
         elementTree.body.statements.forEach(function(statement) {
-          if (statement.expression.type === BINARY_EXPRESSION &&
-              statement.expression.operator.type === '=' &&
-              statement.expression.left.type === MEMBER_EXPRESSION &&
-              statement.expression.left.operand.type === THIS_EXPRESSION) {
+          var exp = statement.expression;
+          if (exp.type === BINARY_EXPRESSION &&
+              exp.operator.type === EQUAL &&
+              exp.left.type === MEMBER_EXPRESSION &&
+              exp.left.operand.type === THIS_EXPRESSION) {
 
-            var typeAnnotation = argumentTypesMap[statement.expression.left.memberName.value] || null;
-            fields.push(new ClassFieldParseTree(tree.location, statement.expression.left.memberName, typeAnnotation));
+            var typeAnnotation;
+
+            if (exp.right.type === IDENTIFIER_EXPRESSION) {
+              // `this.field = variable;`
+              // we can infer the type of the field from the variable when it is a typed arg
+              var varName = exp.right.getStringValue();
+              typeAnnotation = argumentTypesMap[varName] || null;
+            }
+
+            var fieldName = exp.left.memberName.value;
+            var lvalue = new BindingIdentifier(tree.location, fieldName);
+            fields.push(new ClassFieldDeclaration(tree.location, lvalue, typeAnnotation, isConst));
           }
         });
+
+        // Compute the initializer list
+        var initializerList = [];
+        var superCall = that._extractSuperCall(elementTree.body);
+        if (isConst) {
+          initializerList = that._extractFieldInitializers(elementTree.body);
+          if (elementTree.body.statements.length > 0) {
+            that.reporter_.reportError(
+              elementTree.location,
+              'Const constructor body can only contain field initialization & super call');
+          }
+        }
+        if (superCall) initializerList.push(superCall);
+
+        // Replace the `PROPERTY_METHOD_ASSIGNMENT` with a Dart specific
+        // `PROPERTY_CONSTRUCTOR_ASSIGNMENT`
+        tree.elements[index] = new PropertyConstructorAssignment(
+          elementTree.location,
+          elementTree.isStatic,
+          elementTree.functionKind,
+          elementTree.name,
+          elementTree.parameterList,
+          elementTree.typeAnnotation,
+          elementTree.annotations,
+          elementTree.body,
+          isConst,
+          initializerList
+        );
       }
     });
 
@@ -64,5 +127,58 @@ export class ClassTransformer extends ParseTreeTransformer {
     tree.elements = fields.concat(tree.elements);
 
     return super(tree);
-  };
+  }
+
+  /**
+   * Extract field initialization (`this.field = <expression>;`) from the body of the constructor.
+   * The init statements are removed from the body statements and returned as an array.
+   */
+  _extractFieldInitializers(body) {
+    var statements = [];
+    var fieldInitializers = [];
+    body.statements.forEach(function(statement) {
+      var exp = statement.expression;
+      if (exp.type === BINARY_EXPRESSION &&
+          exp.operator.type === EQUAL &&
+          exp.left.type === MEMBER_EXPRESSION &&
+          exp.left.operand.type === THIS_EXPRESSION) {
+          // `this.field = exp` -> `field = exp`
+          // todo(vicb): check for `this.` on rhs, not allowed in Dart
+          // -> remove if possible (arguments), throw otherwise.
+        var fieldName = exp.left.memberName.value;
+        fieldInitializers.push(new BinaryExpression(
+          statement.location,
+          new IdentifierExpression(statement.location, fieldName),
+          EQUAL,
+          exp.right
+        ));
+      } else {
+        statements.push(statement);
+      }
+    });
+
+    body.statements = statements;
+    return fieldInitializers;
+  }
+
+  /**
+   * Extract the super call (`super(<arg list>)`) from the body of the constructor.
+   * When found the super call statement is removed from the body statements and returned.
+   */
+  _extractSuperCall(body) {
+    var statements = [];
+    var superCall = null;
+
+    body.statements.forEach(function (statement) {
+      if (statement.expression.type === CALL_EXPRESSION &&
+          statement.expression.operand.type === SUPER_EXPRESSION) {
+        superCall = statement.expression;
+      } else {
+        statements.push(statement);
+      }
+    });
+
+    body.statements = statements;
+    return superCall;
+  }
 }

tools/transpiler/src/codegeneration/InstanceOfTransformer.js

@@ -1,6 +1,6 @@
 import {INSTANCEOF} from 'traceur/src/syntax/TokenType';
 
-import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+import {ParseTreeTransformer} from './ParseTreeTransformer';
 
 /**
  * Transforms `a instanceof b` to `a is b`,

tools/transpiler/src/codegeneration/MultiVarTransformer.js

@@ -1,6 +1,6 @@
 import {VariableStatement, VariableDeclarationList} from 'traceur/src/syntax/trees/ParseTrees';
 
-import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+import {ParseTreeTransformer} from './ParseTreeTransformer';
 
 /**
  * Transforms `var a, b;` to `var a; var b;`

tools/transpiler/src/codegeneration/ParseTreeTransformer.js

@@ -0,0 +1,31 @@
+import {
+  ParseTreeTransformer as TraceurParseTreeTransformer
+} from 'traceur/src/codegeneration/ParseTreeTransformer';
+
+import {
+  ClassFieldDeclaration,
+  PropertyConstructorAssignment
+} from '../syntax/trees/ParseTrees'
+
+export class ParseTreeTransformer extends TraceurParseTreeTransformer {
+  transformClassFieldDeclaration(tree) {
+    var lvalue = this.transformAny(tree.lvalue);
+    var typeAnnotation = this.transformAny(tree.typeAnnotation);
+    if (lvalue === tree.lvalue && typeAnnotation === tree.typeAnnotation) {
+      return tree;
+    }
+    return new ClassFieldDeclaration(tree.location, lvalue, typeAnnotation, initializer);
+  }
+
+  transformPropertyConstructorAssignment(tree) {
+    tree = super.transformPropertyMethodAssignment(tree);
+    var initializerList = this.transformList(tree.initializerList);
+    if (initializerList === tree.initializerList) {
+      return tree;
+    }
+
+    return new PropertyConstructorAssignment(tree.location, tree.isStatic, tree.functionKind,
+      tree.name, tree.parameterList, tree.typeAnnotation, tree.annotations, tree.body, tree.isConst,
+      initializerList);
+  }
+}

tools/transpiler/src/codegeneration/StrictEqualityTransformer.js

@@ -1,14 +1,15 @@
 import {
+  createArgumentList,
   createCallExpression,
-  createIdentifierExpression,
-  createArgumentList} from 'traceur/src/codegeneration/ParseTreeFactory';
+  createIdentifierExpression
+} from 'traceur/src/codegeneration/ParseTreeFactory';
 
 import {
   EQUAL_EQUAL_EQUAL,
   NOT_EQUAL_EQUAL
 } from 'traceur/src/syntax/TokenType';
 
-import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+import {ParseTreeTransformer} from './ParseTreeTransformer';
 
 /**
  * Transforms:

tools/transpiler/src/compiler.js

@@ -1,6 +1,6 @@
 import {Compiler as TraceurCompiler} from 'traceur/src/Compiler';
 import {DartTransformer} from './codegeneration/DartTransformer';
-import {DartTreeWriter} from './dart_writer';
+import {DartParseTreeWriter} from './outputgeneration/DartParseTreeWriter';
 import {CollectingErrorReporter} from 'traceur/src/util/CollectingErrorReporter';
 import {Parser} from './parser';
 import {SourceFile} from 'traceur/src/syntax/SourceFile';
@@ -28,7 +28,7 @@ export class Compiler extends TraceurCompiler {
 
   write(tree, outputName = undefined, sourceRoot = undefined) {
     if (this.options_.outputLanguage.toLowerCase() === 'dart') {
-      var writer = new DartTreeWriter(this.options_.moduleName, outputName);
+      var writer = new DartParseTreeWriter(this.options_.moduleName, outputName);
       writer.visitAny(tree);
       return writer.toString();
     } else {

tools/transpiler/src/outputgeneration/DartParseTreeWriter.js

@@ -1,9 +1,22 @@
 import {CONSTRUCTOR, FROM} from 'traceur/src/syntax/PredefinedName';
-import {EQUAL_EQUAL_EQUAL, OPEN_PAREN, CLOSE_PAREN, IMPORT, SEMI_COLON, STAR, OPEN_CURLY, CLOSE_CURLY, COMMA, AT, EQUAL, COLON} from 'traceur/src/syntax/TokenType';
+import {
+  AT,
+  CLOSE_CURLY,
+  CLOSE_PAREN,
+  COLON,
+  COMMA,
+  EQUAL,
+  EQUAL_EQUAL_EQUAL,
+  IMPORT,
+  OPEN_CURLY,
+  OPEN_PAREN,
+  SEMI_COLON,
+  STAR
+} from 'traceur/src/syntax/TokenType';
 
 import {ParseTreeWriter as JavaScriptParseTreeWriter, ObjectLiteralExpression} from 'traceur/src/outputgeneration/ParseTreeWriter';
 
-export class DartTreeWriter extends JavaScriptParseTreeWriter {
+export class DartParseTreeWriter extends JavaScriptParseTreeWriter {
   constructor(moduleName, outputPath) {
     super(outputPath);
     this.libName = moduleName.replace(/\//g, '.');
@@ -104,20 +117,42 @@ export class DartTreeWriter extends JavaScriptParseTreeWriter {
     this.visitAny(tree.body);
   }
 
+  /**
+   * @param {PropertyMethodAssignment} tree
+   */
+  visitPropertyConstructorAssignment(tree) {
+    this.writeAnnotations_(tree.annotations);
+
+    if (tree.isConst) {
+      this.write_('const');
+      this.writeSpace_();
+    }
+
+    this.writeType_(tree.typeAnnotation);
+    this.visitAny(tree.name);
+    this.write_(OPEN_PAREN);
+    this.visitAny(tree.parameterList);
+    this.write_(CLOSE_PAREN);
+    if (tree.initializerList.length > 0) {
+      this.write_(COLON);
+      this.writeSpace_();
+      this.writeList_(tree.initializerList, ', ');
+    }
+    if (tree.isConst) {
+      this.write_(SEMI_COLON);
+    } else {
+      this.writeSpace_();
+      this.visitAny(tree.body);
+    }
+  }
+
   normalizeType_(typeName) {
-    if (typeName === 'number') {
-      return 'num';
+    switch (typeName) {
+      case 'number': return 'num';
+      case 'boolean': return 'bool';
+      case 'string': return 'String';
+      default: return typeName;
     }
-
-    if (typeName === 'boolean') {
-      return 'bool';
-    }
-
-    if (typeName === 'string') {
-      return 'String';
-    }
-
-    return typeName;
   }
 
   // FUNCTION/METHOD ARGUMENTS
@@ -148,14 +183,23 @@ export class DartTreeWriter extends JavaScriptParseTreeWriter {
     }
   }
 
-  visitClassField(tree) {
-    this.writeType_(tree.typeAnnotation);
-
-    if (!tree.typeAnnotation) {
-      this.write_('var ');
+  visitClassFieldDeclaration(tree) {
+    if (tree.isFinal) {
+      // `final <type> name;` or `final name;` for untyped variable
+      this.write_('final');
+      this.writeSpace_();
+      this.writeType_(tree.typeAnnotation);
+    } else {
+      // `<type> name;` or `var name;`
+      if (tree.typeAnnotation) {
+        this.writeType_(tree.typeAnnotation);
+      } else {
+        this.write_('var');
+        this.writeSpace_();
+      }
     }
 
-    this.write_(tree.identifier);
+    this.write_(tree.lvalue.getStringValue());
     this.write_(SEMI_COLON);
   }
 
@@ -179,7 +223,8 @@ export class DartTreeWriter extends JavaScriptParseTreeWriter {
   // EXPORTS
   visitExportDeclaration(tree) {
     if (tree.declaration.moduleSpecifier) {
-      this.write_('export ');
+      this.write_('export');
+      this.writeSpace_();
       this.visitModuleSpecifier(tree.declaration.moduleSpecifier);
       this.write_(SEMI_COLON);
     } else {

tools/transpiler/src/syntax/trees/ParseTreeType.js

@@ -0,0 +1,2 @@
+export var CLASS_FIELD_DECLARATION = 'CLASS_FIELD_DECLARATION';
+export var PROPERTY_CONSTRUCTOR_ASSIGNMENT = 'PROPERTY_CONSTRUCTOR_ASSIGNMENT';

tools/transpiler/src/syntax/trees/ParseTrees.js

@@ -0,0 +1,80 @@
+import {ParseTree} from 'traceur/src/syntax/trees/ParseTree';
+
+import {PropertyMethodAssignment} from 'traceur/src/syntax/trees/ParseTrees';
+
+import * as ParseTreeType from './ParseTreeType';
+
+/**
+ * Property declaration
+ */
+export class ClassFieldDeclaration extends ParseTree {
+  constructor(location, lvalue, typeAnnotation, isFinal) {
+    this.location = location;
+    this.lvalue = lvalue;
+    this.typeAnnotation = typeAnnotation;
+    this.isFinal = isFinal;
+  }
+
+  get type() {
+    return CLASS_FIELD_DECLARATION;
+  }
+
+  visit(visitor) {
+    visitor.visitClassFieldDeclaration(this);
+  }
+
+  transform(transformer) {
+    return transformer.transformClassFieldDeclaration(this);
+  }
+}
+
+var CLASS_FIELD_DECLARATION = ParseTreeType.CLASS_FIELD_DECLARATION;
+
+/**
+ * Class constructor
+ */
+export class PropertyConstructorAssignment extends PropertyMethodAssignment {
+  /**
+   * @param {SourceRange} location
+   * @param {boolean} isStatic
+   * @param {Token} functionKind
+   * @param {ParseTree} name
+   * @param {FormalParameterList} parameterList
+   * @param {ParseTree} typeAnnotation
+   * @param {Array.<ParseTree>} annotations
+   * @param {FunctionBody} body
+   * @param {boolean} isConst
+   * @param {ParseTree} initializerList
+   */
+  constructor(location, isStatic, functionKind, name, parameterList, typeAnnotation, annotations,
+              body, isConst, initializerList) {
+    super(location, isStatic, functionKind, name, parameterList, typeAnnotation, annotations,
+          body);
+    this.isConst = isConst;
+    this.initializerList = initializerList;
+  }
+
+  /**
+   * @param {ParseTreeTransformer} transformer
+   */
+  transform(transformer) {
+    return transformer.transformPropertyConstructorAssignment(this);
+  }
+
+  /**
+   * @param {ParseTreeVisitor} visitor
+   */
+  visit(visitor) {
+    visitor.visitPropertyConstructorAssignment(this);
+  }
+
+  /**
+   * @type {ParseTreeType}
+   */
+  get type() {
+    return PROPERTY_CONSTRUCTOR_ASSIGNMENT;
+  }
+}
+
+var PROPERTY_CONSTRUCTOR_ASSIGNMENT = ParseTreeType.PROPERTY_CONSTRUCTOR_ASSIGNMENT;
+