- Added %IsArrayClass, %IsDateClass, and %IsStringClass....

src/string.js

 // Copyright 2006-2008 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 28 matching lines @@
     %_SetValueOf(this, value);
   } else {
     return value;
   }
 });
 
 %FunctionSetPrototype($String, new $String());
 
 // ECMA-262 section 15.5.4.2
 function StringToString() {
-  if (!IS_STRING(this) && %ClassOf(this) !== 'String')
+  if (!IS_STRING(this) && !%IsStringClass(this))
     throw new $TypeError('String.prototype.toString is not generic');
   return %_ValueOf(this);
 }
 
 
 // ECMA-262 section 15.5.4.3
 function StringValueOf() {
-  if (!IS_STRING(this) && %ClassOf(this) !== 'String')
+  if (!IS_STRING(this) && !%IsStringClass(this))
     throw new $TypeError('String.prototype.valueOf is not generic');
   return %_ValueOf(this);
 }
 
 
 // ECMA-262, section 15.5.4.4
 function StringCharAt(pos) {
   var subject = ToString(this);
   var index = TO_INTEGER(pos);
   if (index >= subject.length || index < 0) return "";
@@ skipping 757 matching lines @@
     "italics", StringItalics,
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup
   ));
 }
 
 
 SetupString();