ES6 symbols: Implement Symbol intrinsic and basic functionality

test/mjsunit/harmony/symbols.js

Index: test/mjsunit/harmony/symbols.js
diff --git a/test/mjsunit/harmony/symbols.js b/test/mjsunit/harmony/symbols.js
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+// Copyright 2012 the V8 project authors. All rights reserved.

[Michael Starzinger, 2013/02/26 20:41:49]

The copyright header should say 2013 here.

[rossberg, 2013/02/27 13:12:23]

Done.

+// 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// 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-symbols --harmony-collections
+// Flags: --expose-gc --allow-natives-syntax
+
+var symbols = []
+
+// Test different forms of constructor calls, all equivalent.
+function TestNew() {
+  function IndirectSymbol() { return new Symbol }
+  function indirect() { return new IndirectSymbol() }
+  for (var i = 0; i < 10; ++i) {
+    symbols.push(new Symbol)
+    symbols.push(new Symbol())
+    symbols.push(Symbol())
+    symbols.push(indirect())
+  }
+  %OptimizeFunctionOnNextCall(indirect)
+  indirect()

[Michael Starzinger, 2013/02/26 20:41:49]

Could you add a comment like "// Call once before GC to preserve type feedback."
to the end of this line which explains why indirect() is called here?

[rossberg, 2013/02/27 13:12:23]

Done.

+  gc();  // Promote, and then allocate some more.
+  for (var i = 0; i < 10; ++i) {
+    symbols.push(new Symbol)
+    symbols.push(new Symbol())
+    symbols.push(Symbol())
+    symbols.push(indirect())
+  }
+}
+TestNew()
+
+
+function TestType() {
+  for (var i in symbols) {
+    assertTrue(%_IsSymbol(symbols[i]))
+    assertEquals("object", typeof symbols[i])
+    assertTrue(typeof symbols[i] === "object")
+    assertEquals("[object Symbol]", Object.prototype.toString.call(symbols[i]))
+  }
+}
+TestType()
+
+
+function TestEquality() {
+  // Every symbol should equal itself.
+  for (var i in symbols) {
+    assertSame(symbols[i], symbols[i])
+    assertEquals(symbols[i], symbols[i])
+    assertTrue(Object.is(symbols[i], symbols[i]))
+    assertTrue(symbols[i] === symbols[i])
+    assertTrue(symbols[i] == symbols[i])
+  }
+
+  // All symbols should be distinct.
+  for (var i = 0; i < symbols.length; ++i) {
+    for (var j = i + 1; j < symbols.length; ++j) {
+      assertFalse(Object.is(symbols[i], symbols[j]))
+      assertFalse(symbols[i] === symbols[j])
+      assertFalse(symbols[i] == symbols[j])
+    }
+  }
+}
+TestEquality()
+
+
+function TestGet() {
+  for (var i in symbols) {
+    assertEquals("[object Symbol]", symbols[i].toString())
+    assertEquals(undefined, symbols[i].valueOf)
+    assertEquals(undefined, symbols[i].a)
+    assertEquals(undefined, symbols[i]["a" + "b"])
+    assertEquals(undefined, symbols[i]["" + "1"])
+    assertEquals(undefined, symbols[i][62])
+  }
+}
+TestGet()
+
+
+function TestSet() {
+  for (var i in symbols) {
+    symbols[i].toString = 0
+    assertEquals("[object Symbol]", symbols[i].toString())
+    symbols[i].a = 0
+    assertEquals(undefined, symbols[i].a)
+    symbols[i]["a" + "b"] = 0
+    assertEquals(undefined, symbols[i]["a" + "b"])
+    symbols[i][62] = 0
+    assertEquals(undefined, symbols[i][62])
+  }
+}
+TestSet()
+
+
+function TestMap() {
+  var map = new Map;
+  for (var i in symbols) {
+    map.set(symbols[i], i)
+  }
+  for (var i in symbols) {

[Michael Starzinger, 2013/02/26 20:41:49]

Could you also add a assertTrue(map.has(symbols[i])) check here?

[rossberg, 2013/02/27 13:12:23]

Done.

+    assertEquals(i, map.get(symbols[i]))
+  }
+}
+TestMap()