Implement basic code generation for arrow functions

test/mjsunit/harmony/arrow-functions.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-arrow-functions
+
+// Arrow functions are like functions, except they throw when using the
+// "new" operator on them.
+assertEquals("function", typeof (() => {}));
+assertEquals(Function.prototype, Object.getPrototypeOf(() => {}));
+assertThrows("new (() => {})", TypeError);
+
+// Check the different syntax variations
+assertEquals(1, (() => 1)());
+assertEquals(2, (a => a + 1)(1));
+assertEquals(3, (() => { return 3; })());
+assertEquals(4, (a => { return a + 3; })(1));
+assertEquals(5, ((a, b) => a + b)(1, 4));
+assertEquals(6, ((a, b) => { return a + b; })(1, 5));
+
+// The following are tests from:
+// http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax
+
+// Empty arrow function returns undefined
+var empty = () => {};
+assertEquals(undefined, empty());
+
+// Single parameter case needs no parentheses around parameter list
+var identity = x => x;
+assertEquals(empty, identity(empty));
+
+// No need for parentheses even for lower-precedence expression body
+var square = x => x * x;
+assertEquals(9, square(3));
+
+// Parenthesize the body to return an object literal expression
+var key_maker = val => ({key: val});
+assertEquals(empty, key_maker(empty).key);
+
+// Statement body needs braces, must use 'return' explicitly if not void
+var evens = [0, 2, 4, 6, 8];
+assertEquals([1, 3, 5, 7, 9], evens.map(v => v + 1));
+
+var fives = [];
+[1, 2, 3, 4, 5, 6, 7, 8, 9, 10].forEach(v => {
+  if (v % 5 === 0) fives.push(v);
+});
+assertEquals([5, 10], fives);