diff --git a/version3.0/nasal_gc.h b/version3.0/nasal_gc.h
index a663b66..25d9ad0 100644
--- a/version3.0/nasal_gc.h
+++ b/version3.0/nasal_gc.h
@@ -25,7 +25,6 @@ public:
     int  size();
     int  get_value_address(int);
     int  get_mem_address(int);
-    void deepcopy(nasal_vector&);
 };
 
 class nasal_hash
@@ -40,7 +39,6 @@ public:
     void del_elem(std::string);
     int  get_value_address(std::string);
     int  get_mem_address(std::string);
-    void deepcopy(nasal_hash&);
 };
 
 class nasal_function
@@ -59,7 +57,6 @@ public:
     nasal_ast& get_arguments();
     void set_run_block(nasal_ast&);
     nasal_ast& get_run_block();
-    void deepcopy(nasal_function&);
 };
 
 class nasal_closure
@@ -99,7 +96,6 @@ public:
     nasal_hash&     get_hash();
     nasal_function& get_func();
     nasal_closure&  get_closure();
-    void deepcopy(nasal_scalar&);
     // parameter: memory_manager_memory address
     int nasal_scalar_add(int,int);
     int nasal_scalar_sub(int,int);
@@ -227,20 +223,6 @@ int nasal_vector::get_mem_address(int index)
     }
     return elems[(index+vec_size)%vec_size];
 }
-void nasal_vector::deepcopy(nasal_vector& tmp)
-{
-    int tmp_size=tmp.elems.size();
-    for(int i=0;i<tmp_size;++i)
-    {
-        int new_mem_addr=nasal_vm.mem_alloc();
-        int new_value_addr=nasal_vm.gc_alloc();
-        nasal_vm.mem_init(new_mem_addr,new_value_addr);
-        int tmp_elems_value_addr=nasal_vm.mem_get(tmp.elems[i]);
-        nasal_vm.gc_get(new_value_addr).deepcopy(nasal_vm.gc_get(tmp_elems_value_addr));
-        this->elems.push_back(new_mem_addr);
-    }
-    return;
-}
 
 /*functions of nasal_hash*/
 nasal_hash::nasal_hash()
@@ -328,19 +310,6 @@ int nasal_hash::get_mem_address(std::string key)
     }
     return ret_mem_addr;
 }
-void nasal_hash::deepcopy(nasal_hash& tmp)
-{
-    for(std::map<std::string,int>::iterator iter=tmp.elems.begin();iter!=tmp.elems.end();++iter)
-    {
-        int new_mem_addr=nasal_vm.mem_alloc();
-        int new_value_addr=nasal_vm.gc_alloc();
-        nasal_vm.mem_init(new_mem_addr,new_value_addr);
-        int tmp_value_addr=nasal_vm.mem_get(iter->second);
-        nasal_vm.gc_get(new_value_addr).deepcopy(nasal_vm.gc_get(tmp_value_addr));
-        this->elems[iter->first]=new_mem_addr;
-    }
-    return;
-}
 
 /*functions of nasal_function*/
 nasal_function::nasal_function()
@@ -390,16 +359,6 @@ nasal_ast& nasal_function::get_run_block()
 {
     return function_expr;
 }
-void nasal_function::deepcopy(nasal_function& tmp)
-{
-    if(this->closure_addr>=0)
-        nasal_vm.del_reference(this->closure_addr);
-    this->closure_addr=tmp.closure_addr;
-    nasal_vm.add_reference(tmp.closure_addr);
-    this->argument_list=tmp.argument_list;
-    this->function_expr=tmp.function_expr;
-    return;
-}
 
 /*functions of nasal_closure*/
 nasal_closure::nasal_closure()
@@ -604,22 +563,7 @@ nasal_closure& nasal_scalar::get_closure()
     else
         return error_closure;
 }
-void nasal_scalar::deepcopy(nasal_scalar& tmp)
-{
-    this->clear();
-    this->type=tmp.type;
-    switch(tmp.type)
-    {
-        case vm_nil:      break;
-        case vm_number:   this->scalar_ptr=(void*)(new double);*(double*)this->scalar_ptr=tmp.get_number();break;
-        case vm_string:   this->scalar_ptr=(void*)(new std::string);*(std::string*)this->scalar_ptr=tmp.get_string();break;
-        case vm_vector:   this->scalar_ptr=(void*)(new nasal_vector);(*(nasal_vector*)this->scalar_ptr).deepcopy(tmp.get_vector());break;
-        case vm_hash:     this->scalar_ptr=(void*)(new nasal_hash);(*(nasal_hash*)this->scalar_ptr).deepcopy(tmp.get_hash());break;
-        case vm_function: this->scalar_ptr=(void*)(new nasal_function);(*(nasal_function*)this->scalar_ptr).deepcopy(tmp.get_func());break;
-        case vm_closure:  this->scalar_ptr=(void*)(new nasal_closure);(*(nasal_closure*)this->scalar_ptr).set_closure(tmp.get_closure());break;
-    }
-    return;
-}
+
 int nasal_scalar::nasal_scalar_add(int a_scalar_addr,int b_scalar_addr)
 {
     if(a_scalar_addr<0 || b_scalar_addr<0)
diff --git a/version3.0/nasal_runtime.h b/version3.0/nasal_runtime.h
index ba65ec4..b924f41 100644
--- a/version3.0/nasal_runtime.h
+++ b/version3.0/nasal_runtime.h
@@ -727,20 +727,12 @@ int nasal_runtime::call_vector(nasal_ast& node,int base_value_addr,int local_sco
                 called_value_addrs.push_back(reference_value.get_value_address(index_num));
             }
         }
+        // generate sub-vector
         if(called_value_addrs.size()==1)
         {
             int value_addr=called_value_addrs[0];
-            int value_type=nasal_vm.gc_get(value_addr).get_type();
-            if(value_type==vm_vector || value_type==vm_hash)
-            {
-                nasal_vm.add_reference(value_addr);
-                return_value_addr=value_addr;
-            }
-            else
-            {
-                return_value_addr=nasal_vm.gc_alloc();
-                nasal_vm.gc_get(return_value_addr).deepcopy(nasal_vm.gc_get(value_addr));
-            }
+            nasal_vm.add_reference(value_addr);
+            return_value_addr=value_addr;
         }
         else
         {
@@ -751,18 +743,8 @@ int nasal_runtime::call_vector(nasal_ast& node,int base_value_addr,int local_sco
             for(int i=0;i<vec_size;++i)
             {
                 int value_addr=called_value_addrs[i];
-                int value_type=nasal_vm.gc_get(value_addr).get_type();
-                if(value_type==vm_vector || value_type==vm_hash)
-                {
-                    nasal_vm.add_reference(value_addr);
-                    return_vector.add_elem(value_addr);
-                }
-                else
-                {
-                    int tmp_value_addr=nasal_vm.gc_alloc();
-                    nasal_vm.gc_get(tmp_value_addr).deepcopy(nasal_vm.gc_get(value_addr));
-                    return_vector.add_elem(tmp_value_addr);
-                }
+                nasal_vm.add_reference(value_addr);
+                return_vector.add_elem(value_addr);
             }
         }
     }
@@ -782,17 +764,8 @@ int nasal_runtime::call_vector(nasal_ast& node,int base_value_addr,int local_sco
         }
         std::string str=node.get_children()[0].get_str();
         int value_addr=nasal_vm.gc_get(base_value_addr).get_hash().get_value_address(str);
-        int value_type=nasal_vm.gc_get(value_addr).get_type();
-        if(value_type==vm_vector || value_type==vm_hash)
-        {
-            nasal_vm.add_reference(value_addr);
-            return_value_addr=value_addr;
-        }
-        else
-        {
-            return_value_addr=nasal_vm.gc_alloc();
-            nasal_vm.gc_get(return_value_addr).deepcopy(nasal_vm.gc_get(value_addr));
-        }
+        nasal_vm.add_reference(value_addr);
+        return_value_addr=value_addr;
     }
     else
     {
@@ -1508,14 +1481,6 @@ void nasal_runtime::definition(nasal_ast& node,int local_scope_addr)
             for(int i=0;i<val_size;++i)
             {
                 int tmp_addr=calculation(value_node.get_children()[i],local_scope_addr);
-                int type=nasal_vm.gc_get(tmp_addr).get_type();
-                if(type!=vm_vector && type!=vm_hash)
-                {
-                    int new_addr=nasal_vm.gc_alloc();
-                    nasal_vm.gc_get(new_addr).deepcopy(nasal_vm.gc_get(tmp_addr));
-                    nasal_vm.del_reference(tmp_addr);
-                    tmp_addr=new_addr;
-                }
                 nasal_vm.gc_get(local_scope_addr<0?global_scope_address:local_scope_addr).get_closure().add_new_value(identifier_table[i],tmp_addr);
             }
         }
@@ -1538,13 +1503,6 @@ void nasal_runtime::definition(nasal_ast& node,int local_scope_addr)
             for(int i=0;i<id_size;++i)
             {
                 int tmp_addr=ref_vector.get_value_address(i);
-                int type=nasal_vm.gc_get(tmp_addr).get_type();
-                if(type!=vm_vector && type!=vm_hash)
-                {
-                    int new_addr=nasal_vm.gc_alloc();
-                    nasal_vm.gc_get(new_addr).deepcopy(nasal_vm.gc_get(tmp_addr));
-                    tmp_addr=new_addr;
-                }
                 nasal_vm.gc_get(local_scope_addr<0?global_scope_address:local_scope_addr).get_closure().add_new_value(identifier_table[i],tmp_addr);
             }
             nasal_vm.del_reference(value_addr);
@@ -1581,14 +1539,6 @@ void nasal_runtime::multi_assignment(nasal_ast& node,int local_scope_addr)
         for(int i=0;i<val_size;++i)
         {
             int tmp_addr=calculation(value_node.get_children()[i],local_scope_addr);
-            int type=nasal_vm.gc_get(tmp_addr).get_type();
-            if(type!=vm_vector && type!=vm_hash)
-            {
-                int new_addr=nasal_vm.gc_alloc();
-                nasal_vm.gc_get(new_addr).deepcopy(nasal_vm.gc_get(tmp_addr));
-                nasal_vm.del_reference(tmp_addr);
-                tmp_addr=new_addr;
-            }
             nasal_vm.mem_change(mem_table[i],tmp_addr);
         }
     }
@@ -1613,13 +1563,6 @@ void nasal_runtime::multi_assignment(nasal_ast& node,int local_scope_addr)
         for(int i=0;i<id_size;++i)
         {
             int tmp_addr=ref_vector.get_value_address(i);
-            int type=nasal_vm.gc_get(tmp_addr).get_type();
-            if(type!=vm_vector && type!=vm_hash)
-            {
-                int new_addr=nasal_vm.gc_alloc();
-                nasal_vm.gc_get(new_addr).deepcopy(nasal_vm.gc_get(tmp_addr));
-                tmp_addr=new_addr;
-            }
             nasal_vm.mem_change(mem_table[i],tmp_addr);
         }
         nasal_vm.del_reference(value_addr);