feat(transpiler): implement @implements

Author: vsavkin

tools/transpiler/spec/interfaces_spec.js

@@ -0,0 +1,22 @@
+import {ddescribe, describe, it, expect, IS_DARTIUM} from 'test_lib/test_lib';
+import {IMPLEMENTS} from './fixtures/annotations';
+
+class Interface1 {}
+class Interface2 {}
+
+@IMPLEMENTS(Interface1, Interface2)
+class SomeClass {}
+
+export function main() {
+  describe('interfaces', function() {
+    //TODO: remvoe when interfaces are supported in AtScript
+    if (IS_DARTIUM) {
+      it('should work', function () {
+        var s = new SomeClass();
+        expect(s instanceof Interface1).toBeTrue();
+        expect(s instanceof Interface2).toBeTrue();
+      });
+    }
+  });
+
+}

tools/transpiler/src/codegeneration/ClassTransformer.js

@@ -25,7 +25,8 @@ import {
 } from 'traceur/src/syntax/trees/ParseTrees';
 
 import {
-  PropertyConstructorAssignment
+  PropertyConstructorAssignment,
+  ImplementsDeclaration
 } from '../syntax/trees/ParseTrees';
 
 /**
@@ -122,6 +123,13 @@ export class ClassTransformer extends ParseTreeTransformer {
       }
     }
 
+    let implementsAnnotation = this._extractImplementsAnnotation(tree);
+    if (implementsAnnotation !== null) {
+      tree.implements = new ImplementsDeclaration(
+        implementsAnnotation.location,
+        implementsAnnotation.args.args);
+    }
+
     // Add the field definitions to the beginning of the class.
     tree.elements = fields.concat(tree.elements);
     if (isConst) {
@@ -187,31 +195,50 @@ export class ClassTransformer extends ParseTreeTransformer {
     return superCall;
   }
 
+  /**
+   * Extract the @IMPLEMENTS annotation from the class annotations.
+   * When found the annotation is removed from the class annotations and returned.
+   */
+  _extractImplementsAnnotation(tree) {
+    return this._extractAnnotation(tree, this._isImplementsAnnotation);
+  }
+
   /**
    * Extract the @CONST annotation from the class annotations.
    * When found the annotation is removed from the class annotations and returned.
    */
   _extractConstAnnotation(tree) {
+    return this._extractAnnotation(tree, this._isConstAnnotation);
+  }
+
+  _extractAnnotation(tree, predicate) {
     var annotations = [];
-    var constAnnotation = null;
-    var that = this;
+    var extractedAnnotation = null;
 
     tree.annotations.forEach((annotation) => {
-      if (that._isConstAnnotation(annotation)) {
-        constAnnotation = annotation;
+      if (predicate(annotation)) {
+        extractedAnnotation = annotation;
       } else {
         annotations.push(annotation);
       }
     });
 
     tree.annotations = annotations;
-    return constAnnotation;
+    return extractedAnnotation;
   }
+
   /**
    * Returns true if the annotation is @CONST
    */
   _isConstAnnotation(annotation) {
     return annotation.name.identifierToken.value === 'CONST';
   }
 
+  /**
+   * Returns true if the annotation is @IMPLEMENTS
+   */
+  _isImplementsAnnotation(annotation) {
+    return annotation.name.identifierToken.value === 'IMPLEMENTS';
+  }
+
 }

tools/transpiler/src/outputgeneration/DartParseTreeWriter.js

@@ -1,13 +1,16 @@
 import {CONSTRUCTOR, FROM} from 'traceur/src/syntax/PredefinedName';
 import {
   AT,
+  CLASS,
   CLOSE_CURLY,
   CLOSE_PAREN,
   CLOSE_SQUARE,
   COLON,
   COMMA,
   EQUAL,
   EQUAL_EQUAL_EQUAL,
+  EXTENDS,
+  IMPLEMENTS,
   IMPORT,
   OPEN_CURLY,
   OPEN_PAREN,
@@ -456,6 +459,32 @@ export class DartParseTreeWriter extends JavaScriptParseTreeWriter {
     this.writeList_(tree.parameterNameAndValues, COMMA, false);
   }
 
+  visitClassDeclaration(tree) {
+    this.writeAnnotations_(tree.annotations);
+    this.write_(CLASS);
+    this.writeSpace_();
+    this.visitAny(tree.name);
+
+    if (tree.superClass) {
+      this.writeSpace_();
+      this.write_(EXTENDS);
+      this.writeSpace_();
+      this.visitAny(tree.superClass);
+    }
+
+    if (tree.implements) {
+      this.writeSpace_();
+      this.write_(IMPLEMENTS);
+      this.writeSpace_();
+      this.writeList_(tree.implements.interfaces, COMMA, false);
+    }
+
+    this.writeSpace_();
+    this.write_(OPEN_CURLY);
+    this.writelnList_(tree.elements);
+    this.write_(CLOSE_CURLY);
+  }
+
   toString() {
     return "library " + this.libName + ";\n" + super.toString();
   }

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

@@ -2,3 +2,4 @@ export var CLASS_FIELD_DECLARATION = 'CLASS_FIELD_DECLARATION';
 export var PROPERTY_CONSTRUCTOR_ASSIGNMENT = 'PROPERTY_CONSTRUCTOR_ASSIGNMENT';
 export var NAMED_PARAMETER_LIST = 'NAMED_PARAMETER_LIST';
 export var OBJECT_PATTERN_BINDING_ELEMENT = 'OBJECT_PATTERN_BINDING_ELEMENT';
+export var IMPLEMENTS_DECLARATION = "IMPLEMENTS_DECLARATION";

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

@@ -137,4 +137,41 @@ export class ObjectPatternBindingElement extends ParseTree {
     return OBJECT_PATTERN_BINDING_ELEMENT;
   }
 }
+
+export class ImplementsDeclaration extends ParseTree {
+  /**
+   * @param {SourceRange} location
+   * @param {Array.<ParseTree>} interfaces
+   */
+  constructor(location, interfaces) {
+    this.location = location;
+    this.interfaces = interfaces;
+  }
+
+  /**
+   * @param {ParseTreeTransformer} transformer
+   */
+  transform(transformer) {
+    if (transformer.transformImplementsDeclaration) {
+      return transformer.transformImplementsDeclaration(this);
+    }
+    return this;
+  }
+
+  /**
+   * @param {ParseTreeVisitor} visitor
+   */
+  visit(visitor) {
+    if (visitor.visitImplementsDeclaration) {
+      visitor.visitImplementsDeclaration(this);
+    }
+  }
+
+  /**
+   * @type {ParseTreeType}
+   */
+  get type() {
+    return ParseTreeType.IMPLEMENTS_DECLARATION;
+  }
+}
 var OBJECT_PATTERN_BINDING_ELEMENT = ParseTreeType.OBJECT_PATTERN_BINDING_ELEMENT;