Implement function proxies (except for their use as constructors).

src/string.js

 // Copyright 2006-2009 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 205 matching lines @@
 function StringReplace(search, replace) {
   if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
     throw MakeTypeError("called_on_null_or_undefined",
                         ["String.prototype.replace"]);
   }
   var subject = TO_STRING_INLINE(this);
 
   // Delegate to one of the regular expression variants if necessary.
   if (IS_REGEXP(search)) {
     %_Log('regexp', 'regexp-replace,%0r,%1S', [search, subject]);
-    if (IS_FUNCTION(replace)) {
+    if (IS_SPEC_FUNCTION(replace)) {
       if (search.global) {
         return StringReplaceGlobalRegExpWithFunction(subject, search, replace);
       } else {
         return StringReplaceNonGlobalRegExpWithFunction(subject,
                                                         search,
                                                         replace);
       }
     } else {
       return %StringReplaceRegExpWithString(subject,
                                             search,
                                             TO_STRING_INLINE(replace),
                                             lastMatchInfo);
     }
   }
 
   // Convert the search argument to a string and search for it.
   search = TO_STRING_INLINE(search);
   var start = %StringIndexOf(subject, search, 0);
   if (start < 0) return subject;
   var end = start + search.length;
 
   var builder = new ReplaceResultBuilder(subject);
   // prefix
   builder.addSpecialSlice(0, start);
 
   // Compute the string to replace with.
-  if (IS_FUNCTION(replace)) {
+  if (IS_SPEC_FUNCTION(replace)) {
     var receiver =
         %_IsNativeOrStrictMode(replace) ? void 0 : %GetGlobalReceiver();
     builder.add(%_CallFunction(receiver,
                                search,
                                start,
                                subject,
                                replace));
   } else {
     reusableMatchInfo[CAPTURE0] = start;
     reusableMatchInfo[CAPTURE1] = end;
@@ skipping 726 matching lines @@
     "italics", StringItalics,
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup
   ));
 }
 
 
 SetupString();