ES6 symbols: Implement Symbol intrinsic and basic functionality

test/mjsunit/harmony/symbols.js

+// Copyright 2013 the V8 project authors. All rights reserved.
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+// modification, are permitted provided that the following conditions are
+// met:
+//
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+// 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()  // Call once before GC throws away type feedback.
+  gc()        // Promote existing symbols 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) {
+    assertTrue(map.has(symbols[i]))
+    assertEquals(i, map.get(symbols[i]))
+  }
+}
+TestMap()