diff --git a/lib/lexer.js b/lib/lexer.js
index 665b4f0e..4eda209a 100644
--- a/lib/lexer.js
+++ b/lib/lexer.js
@@ -206,7 +206,10 @@
         });
         this.tokens = this.tokens.concat([['(', '('], ['NEW', 'new'], ['IDENTIFIER', 'RegExp'], ['CALL_START', '(']]);
         this.interpolateString(("\"" + str + "\""), true);
-        this.tokens = this.tokens.concat([[',', ','], ['STRING', ("\"" + flags + "\"")], [')', ')'], [')', ')']]);
+        if (flags) {
+          this.tokens.splice(this.tokens.length, 0, [',', ','], ['STRING', ("\"" + flags + "\"")]);
+        }
+        this.tokens.splice(this.tokens.length, 0, [')', ')'], [')', ')']);
       } else {
         this.token('REGEX', regex);
       }
diff --git a/lib/nodes.js b/lib/nodes.js
index b56a910e..20e54aa5 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -3,9 +3,10 @@
   var __extends = function(child, parent) {
     var ctor = function(){ };
     ctor.prototype = parent.prototype;
-    child.__superClass__ = parent.prototype;
     child.prototype = new ctor();
     child.prototype.constructor = child;
+    if (typeof parent.extended === "function") parent.extended(child);
+    child.__superClass__ = parent.prototype;
   };
   if (typeof process !== "undefined" && process !== null) {
     Scope = require('./scope').Scope;
diff --git a/src/lexer.coffee b/src/lexer.coffee
index e512cefc..dee54605 100644
--- a/src/lexer.coffee
+++ b/src/lexer.coffee
@@ -171,7 +171,8 @@ exports.Lexer: class Lexer
       str: str.replace REGEX_ESCAPE, (escaped) -> '\\' + escaped
       @tokens: @tokens.concat [['(', '('], ['NEW', 'new'], ['IDENTIFIER', 'RegExp'], ['CALL_START', '(']]
       @interpolateString "\"$str\"", yes
-      @tokens: @tokens.concat [[',', ','], ['STRING', "\"$flags\""], [')', ')'], [')', ')']]
+      @tokens.splice @tokens.length, 0, [',', ','], ['STRING', "\"$flags\""] if flags
+      @tokens.splice @tokens.length, 0, [')', ')'], [')', ')']
     else
       @token 'REGEX', regex
     @i: + regex.length