diff --git a/helper/ccnb-parser/visitors/depth-first-visitor.cc b/helper/ccnb-parser/visitors/depth-first-visitor.cc
new file mode 100644
index 0000000..305fff6
--- /dev/null
+++ b/helper/ccnb-parser/visitors/depth-first-visitor.cc
@@ -0,0 +1,110 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "depth-first-visitor.h"
+
+#include "../syntax-tree/blob.h"
+#include "../syntax-tree/udata.h"
+#include "../syntax-tree/tag.h"
+#include "../syntax-tree/dtag.h"
+#include "../syntax-tree/attr.h"
+#include "../syntax-tree/dattr.h"
+#include "../syntax-tree/ext.h"
+
+#include <boost/foreach.hpp>
+
+namespace ns3 {
+namespace ndn {
+namespace CcnbParser {
+
+boost::any
+DepthFirstVisitor::visit (Blob &n, boost::any param)
+{
+  // Buffer n.m_blob;
+  return n.m_blob;
+}
+ 
+boost::any
+DepthFirstVisitor::visit (Udata &n, boost::any param)
+{
+  // std::string n.m_udata;
+  return n.m_udata;
+}
+ 
+boost::any
+DepthFirstVisitor::visit (Tag &n, boost::any param)
+{
+  // std::string n.m_tag;
+  // std::list<Ptr<Block> > n.m_attrs;
+  // std::list<Ptr<Block> > n.m_nestedBlocks;
+  BOOST_FOREACH (Ptr<Block> block, n.m_attrs)
+    {
+      block->accept (*this, param);
+    }
+  BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+    {
+      block->accept (*this, param);
+    }
+  return boost::any();
+}
+
+boost::any
+DepthFirstVisitor::visit (Dtag &n, boost::any param)
+{
+  // std::string n.m_tag;
+  // std::list<Ptr<Block> > n.m_attrs;
+  // std::list<Ptr<Block> > n.m_nestedBlocks;
+  BOOST_FOREACH (Ptr<Block> block, n.m_attrs)
+    {
+      block->accept (*this, param);
+    }
+  BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+    {
+      block->accept (*this, param);
+    }
+  return boost::any ();
+}
+
+boost::any
+DepthFirstVisitor::visit (Attr &n, boost::any param)
+{
+  // std::string n.m_attr;
+  // Ptr<Udata> n.m_value;
+  return boost::any ();
+}
+
+boost::any
+DepthFirstVisitor::visit (Dattr &n, boost::any param)
+{
+  // uint32_t n.m_dattr;
+  // Ptr<Udata> n.m_value;
+  return boost::any ();
+}
+ 
+boost::any
+DepthFirstVisitor::visit (Ext &n, boost::any param)
+{
+  // uint64_t n.m_extSubtype;
+  return n.m_extSubtype;
+}
+
+}
+}
+}