Add @@iterator for generator objects

test/mjsunit/harmony/generators-runtime.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 11 matching lines @@
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --harmony-generators
 
 // Test aspects of the generator runtime.
 
-// FIXME(wingo): Replace this reference with a more official link.
 // See:
-// http://wiki.ecmascript.org/lib/exe/fetch.php?cache=cache&media=harmony:es6_generator_object_model_3-29-13.png
+// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-generatorfunction-objects
 
 function f() { }
 function* g() { yield 1; }
 var GeneratorFunctionPrototype = Object.getPrototypeOf(g);
 var GeneratorFunction = GeneratorFunctionPrototype.constructor;
 var GeneratorObjectPrototype = GeneratorFunctionPrototype.prototype;
 
 // A generator function should have the same set of properties as any
 // other function.
 function TestGeneratorFunctionInstance() {
@@ skipping 49 matching lines @@
              Object.getPrototypeOf((function*(){yield 1}).prototype));
 
   var expected_property_names = ["next", "throw", "constructor"];
   var found_property_names =
       Object.getOwnPropertyNames(GeneratorObjectPrototype);
 
   expected_property_names.sort();
   found_property_names.sort();
 
   assertArrayEquals(expected_property_names, found_property_names);
+
+  iterator_desc = Object.getOwnPropertyDescriptor(GeneratorObjectPrototype,
+      Symbol.iterator);
+  assertTrue(iterator_desc !== undefined);
+  assertFalse(iterator_desc.writable);
+  assertFalse(iterator_desc.enumerable);
+  assertFalse(iterator_desc.configurable);
+
+  // The generator object's "iterator" function is just the identity.
+  assertSame(iterator_desc.value.call(42), 42);
 }
 TestGeneratorObjectPrototype();
 
 
 // This tests the object that would be called "GeneratorFunction", if it were
 // like "Function".
 function TestGeneratorFunction() {
   assertSame(GeneratorFunctionPrototype, GeneratorFunction.prototype);
   assertTrue(g instanceof GeneratorFunction);
 
@@ skipping 16 matching lines @@
   assertTrue((function*(){}).prototype !== (function*(){}).prototype);
   assertTrue((function*(){}).prototype !== g.prototype);
   assertTrue(g.prototype instanceof GeneratorFunctionPrototype);
   assertSame(GeneratorObjectPrototype, Object.getPrototypeOf(g.prototype));
   assertTrue(!(g.prototype instanceof Function));
   assertSame(typeof (g.prototype), "object");
 
   assertArrayEquals([], Object.getOwnPropertyNames(g.prototype));
 }
 TestPerGeneratorPrototype();