diff --git a/nasal_codegen.h b/nasal_codegen.h
index 7f8b49b..9b20f2f 100644
--- a/nasal_codegen.h
+++ b/nasal_codegen.h
@@ -168,10 +168,10 @@ struct
 
 struct opcode
 {
-    uint16_t op;
-    uint16_t fidx;
-    uint32_t num;
-    uint32_t line;
+    uint16_t op;  // opcode
+    uint16_t fidx;// source code file index
+    uint32_t num; // imm num
+    uint32_t line;// line of source code
     opcode(uint8_t _op=op_nop,uint16_t _fidx=0,uint32_t _num=0,uint32_t _line=0)
     {
         op=_op;
@@ -448,6 +448,15 @@ void nasal_codegen::func_gen(const nasal_ast& ast)
             gen(op_dynpara,string_table[str],tmp.get_line());
         }
     }
+    // default dynamic parameter name is arg.
+    // if there are too many arguments,unused arguments will be collected to a nasal_vec
+    // if(!ast.get_children().size() || ast.get_children().back().get_type()!=ast_dynamic_id)
+    // {
+    //     const std::string str="arg";
+    //     regist_string(str);
+    //     add_sym(str);
+    //     gen(op_dynpara,string_table[str],ast.get_line());
+    // }
     exec_code[newfunc_label].num=exec_code.size()+1;
     int jmp_ptr=exec_code.size();
     gen(op_jmp,0,0);
diff --git a/nasal_gc.h b/nasal_gc.h
index 05067bf..9358925 100644
--- a/nasal_gc.h
+++ b/nasal_gc.h
@@ -9,6 +9,7 @@ enum nasal_type
     vm_func,
     vm_vec,
     vm_hash,
+    vm_obj,
     vm_type_size
 };
 
@@ -18,10 +19,11 @@ const int increment[vm_type_size]=
 {
     0,    // vm_nil,in fact it is not in use
     65536,// vm_num
-    512,  // vm_str
-    64,   // vm_func
-    2048, // vm_vec
-    512   // vm_hash
+    2048, // vm_str
+    512,  // vm_func
+    8192, // vm_vec
+    512,  // vm_hash
+    0     // vm_obj
 };
 
 // declaration of nasal_val
@@ -29,11 +31,23 @@ struct nasal_val;
 // define nasal_ref => nasal_val*
 typedef nasal_val* nasal_ref;
 
+#ifdef __NASAL_REF__
+struct nasal_ref
+{
+    uint8_t type;
+    union
+    {
+        double num;
+        nasal_val* gcobj;
+    }value;
+};
+#endif
+
 struct nasal_vec// 24 bytes
 {
     std::vector<nasal_ref> elems;
 
-    void        print();
+    void       print();
     nasal_ref  get_val(int);
     nasal_ref* get_mem(int);
 };
@@ -42,7 +56,7 @@ struct nasal_hash// 56 bytes
 {
     std::unordered_map<std::string,nasal_ref> elems;
 
-    void        print();
+    void       print();
     nasal_ref  get_val(std::string&);
     nasal_ref* get_mem(std::string&);
 };
@@ -74,6 +88,7 @@ struct nasal_val// 16 bytes
         nasal_vec*   vec;
         nasal_hash*  hash;
         nasal_func*  func;
+        void*        obj;
     }ptr;
 
     nasal_val(int);
@@ -100,8 +115,7 @@ nasal_ref* nasal_vec::get_mem(int index)
 void nasal_vec::print()
 {
     static int depth=0;
-    ++depth;
-    if(depth>1024)
+    if(++depth>32)
     {
         std::cout<<"[..]";
         --depth;
@@ -173,8 +187,7 @@ nasal_ref* nasal_hash::get_mem(std::string& key)
 void nasal_hash::print()
 {
     static int depth=0;
-    ++depth;
-    if(depth>1024)
+    if(++depth>32)
     {
         std::cout<<"{..}";
         --depth;
diff --git a/nasal_vm.h b/nasal_vm.h
index 1f4b3e6..fe60333 100644
--- a/nasal_vm.h
+++ b/nasal_vm.h
@@ -869,8 +869,12 @@ inline void nasal_vm::opr_ret()
     uint32_t offset=func->offset;
     nasal_ref cls=cls_stk.top();cls_stk.pop();
     // same closure detected,update the last local scope instead of the closure
+    // because when calling a function,local scope get a copy of the func's closure,not the reference
     if(!cls_stk.empty() && cls_stk.top()==cls)
     {
+        // this condition in fact is that two called function are using the same closure
+        // if this copy of closure is changed, the closure will be updated at the same time
+        // also the copy of closure that still in using will alse be updated
         auto& vec=gc.local.back()->ptr.vec->elems;
         auto& func_vec=func->closure->ptr.vec->elems;
         gc.local.pop_back();
@@ -879,6 +883,7 @@ inline void nasal_vm::opr_ret()
     }
     else
     {
+        // two closures are not the same, update the func's closure and drop gc.local.back()
         auto& vec=func->closure->ptr.vec->elems;
         for(uint32_t i=0;i<offset;++i)
             vec[i]=gc.local.back()->ptr.vec->elems[i];
@@ -894,7 +899,7 @@ inline void nasal_vm::opr_ret()
 void nasal_vm::run(std::vector<opcode>& exec,bool op_cnt)
 {
     uint64_t count[op_ret+1]={0};
-    void* opr_table[]=
+    const void* opr_table[]=
     {
         &&nop,     &&intg,     &&intl,   &&offset,
         &&loadg,   &&loadl,    &&pnum,   &&pone,
@@ -918,7 +923,7 @@ void nasal_vm::run(std::vector<opcode>& exec,bool op_cnt)
     };
     
     bytecode=exec;
-    std::vector<void*> code;
+    std::vector<const void*> code;
     for(auto& i:exec)
     {
         code.push_back(opr_table[i.op]);
diff --git a/test/class.nas b/test/class.nas
index 0aa677c..3b50297 100644
--- a/test/class.nas
+++ b/test/class.nas
@@ -21,4 +21,48 @@ println(s.get_age(),' ',s.get_name());
 s.set_age(20);
 s.set_name('Sidi Liang');
 s.print_info();
-println(s.get_age(),' ',s.get_name());
\ No newline at end of file
+println(s.get_age(),' ',s.get_name());
+# flightgear nasal-console cannot use this kind of object initializing
+var m=func(){
+    var (_1,_2)=(0,1);
+    return {
+        a:func(){
+            print(_1,' ',_2,'\n');
+        },
+        b:func(x){
+            _1=x;
+        },
+        c:func(x){
+            _2=x;
+        },
+        d:func(x){
+            return func{
+                print(_1,' ',_2,' ',x,'\n');
+            };
+        },
+        g:func(x){
+            var y=x;
+            return func{
+                print(_1,' ',_2,' ',x,' ',y,'\n');
+            }
+        },
+        h:func(){
+            return func(x){
+                _1=x;
+            }
+        }
+    };
+}();
+
+m.a(); # 0 1
+m.b(2048);
+m.c(1024);
+var a=m.d(-1);
+var b=m.g(1);
+a(); # 2048 1024 -1
+b(); # 2048 1024 1 1
+
+m.h()(2147483647);
+m.a();
+# flightgear-nasal-console: 2147483647 1024
+# nasal-interpreter 2048 1024
\ No newline at end of file