diff --git a/version2.0/nasal_sym.h b/version2.0/nasal_sym.h
deleted file mode 100644
index 059d24d..0000000
--- a/version2.0/nasal_sym.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#ifndef __NASAL_SYM_H__
-#define __NASAL_SYM_H__
-
-// all symbol_map use a same gc system named nasal_gc
-// see detail of nasal_gc in "nasal_gc.h"
-class sym_hash_map
-{
-	private:
-		std::map<std::string,int> sym_map;
-	public:
-		sym_hash_map()
-		{
-			sym_map.clear();
-			return;
-		}
-		sym_hash_map(const sym_hash_map& tmp)
-		{
-			sym_map=tmp.sym_map;
-			for(std::map<std::string,int>::iterator i=sym_map.begin();i!=sym_map.end();++i)
-				nasal_gc.reference_add(i->second);
-			return;
-		}
-		~sym_hash_map()
-		{
-			for(std::map<std::string,int>::iterator i=sym_map.begin();i!=sym_map.end();++i)
-				nasal_gc.reference_delete(i->second);
-			sym_map.clear();
-			nasal_gc.gc_scanner();
-			return;
-		}
-        void set_clear()
-        {
-            sym_map.clear();
-            return;
-        }
-		void add_new_symbol(std::string __sym_name)
-		{
-			if(sym_map.find(__sym_name)==sym_map.end())
-				sym_map[__sym_name]=nasal_gc.gc_alloc();
-			else
-				std::cout<<">> [Runtime] "<<__sym_name<<" exists."<<std::endl;
-			return;
-		}
-		int get_symbol_addr(std::string __sym_name)
-		{
-			if(sym_map.find(__sym_name)!=sym_map.end())
-				return sym_map[__sym_name];
-			else
-				return -1;
-		}
-};
-
-#endif
\ No newline at end of file