From c7cca91770db532620ef6ce880be67eacf6f5028 Mon Sep 17 00:00:00 2001
From: "leon.li" <leon.li@qunar.com>
Date: Mon, 2 Feb 2015 14:46:41 +0800
Subject: [PATCH] add method

---
 lib/transform.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/transform.js b/lib/transform.js
index c3c34f58..4ee11454 100644
--- a/lib/transform.js
+++ b/lib/transform.js
@@ -58,6 +58,8 @@ TreeTransformer.prototype = new TreeWalker;
         node.DEFMETHOD("transform", function(tw, in_list){
             var x, y;
             tw.push(this);
+            this.walker = new TreeWalker;
+            this.walker.stack = tw.stack.concat();
             if (tw.before) x = tw.before(this, descend, in_list);
             if (x === undefined) {
                 if (!tw.after) {
@@ -75,8 +77,10 @@ TreeTransformer.prototype = new TreeWalker;
         });
     };
 
-    function do_list(list, tw) {
-        return MAP(list, function(node){
+    function do_list(list, tw)
+    {
+        return MAP(list, function(node , i){
+            node._position = i;
             return node.transform(tw, true);
         });
     };