diff --git a/lib/ace/lib/lang.js b/lib/ace/lib/lang.js
index 4e6ebf2c..0a0690e8 100644
--- a/lib/ace/lib/lang.js
+++ b/lib/ace/lib/lang.js
@@ -78,14 +78,16 @@ exports.copyArray = function(array){
 };
 
 exports.deepCopy = function (obj) {
-    if (typeof obj != "object") {
+    if (typeof obj !== "object" || !obj)
+        return obj;
+    var cons = obj.constructor;
+    if (cons === RegExp)
         return obj;
-    }
     
-    var copy = obj.constructor();
+    var copy = cons();
     for (var key in obj) {
-        if (typeof obj[key] == "object") {
-            copy[key] = this.deepCopy(obj[key]);
+        if (typeof obj[key] === "object") {
+            copy[key] = exports.deepCopy(obj[key]);
         } else {
             copy[key] = obj[key];
         }