fixes #221, initial sync*, async, async* implementation

test/codegen/language/async_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+
+import 'package:expect/expect.dart';
+
+import 'dart:async';
+
+topLevelFunction() async { }
+
+Future<int> topLevelWithParameter(int a) async {
+  return 7 + a;
+}
+
+topLevelWithParameterWrongType(int a) async {
+  return 7 + a;
+}
+
+var what = 'async getter';
+Future<String> get topLevelGetter async {
+  return 'I want to be an ${what}';
+}
+
+class A {
+  static int staticVar = 1;
+
+  static staticMethod(int param) async => staticVar + param;
+  static get staticGetter async => staticVar + 3;
+
+  int _x;
+  A(this._x);
+
+  operator+(A other) async {
+    return new A(_x + other._x);
+  }
+
+  get value => _x;
+}
+
+class B {
+  final _y;
+  const B._internal(this._y);
+
+  B() : _y = null;
+}
+
+
+main() {
+  var asyncReturn;
+
+  asyncReturn = topLevelFunction();
+  Expect.isTrue(asyncReturn is Future);
+
+  asyncReturn = topLevelWithParameter(4);
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((int result) => Expect.equals(result, 11));
+
+  asyncReturn = topLevelGetter;
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((String result) =>
+      Expect.stringEquals(result, 'I want to be an async getter'));
+
+  asyncReturn = A.staticMethod(2);
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((int result) => Expect.equals(result, 3));
+
+  asyncReturn = A.staticGetter;
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((int result) => Expect.equals(result, 4));
+
+  A a = new A(13);
+
+  var b = new A(9);
+  asyncReturn = a + b;
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((A result) => Expect.equals(result.value, 22));
+
+  var foo = 17;
+  bar(int p1, p2) async {
+    var z = 8;
+    return p2 + z + foo;
+  }
+  asyncReturn = bar(1,2);
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((int result) => Expect.equals(result, 27));
+
+  var moreNesting = (int shadowP1, String p2, num p3) {
+    var z = 3;
+    aa(int shadowP1) async {
+      return foo + z + p3 + shadowP1;
+    }
+    return aa(6);
+  };
+  asyncReturn = moreNesting(1, "ignore", 2);
+  Expect.isTrue(asyncReturn is Future);
+  asyncReturn.then((int result) => Expect.equals(result, 28));
+
+  var checkAsync = (var someFunc) {
+    var toTest = someFunc();
+    Expect.isTrue(toTest is Future);
+    toTest.then((int result) => Expect.equals(result, 4));
+  };
+  checkAsync(() async => 4);
+}