diff --git a/main.cpp b/main.cpp
index 4fdd3b3..f2a84a3 100644
--- a/main.cpp
+++ b/main.cpp
@@ -20,6 +20,7 @@ void help_cmd()
 	<<"    --code        | view bytecode.\n"
 	<<"    --exec        | execute script file.\n"
 	<<"    --time        | execute and get the running time.\n"
+	<<"    --opcnt       | count operands while running.\n"
 	<<"file:\n"
 	<<"    input file name to execute script file.\n";
 	return;
@@ -101,12 +102,12 @@ void execute(std::string& file,std::string& command)
 		codegen.get_num_table(),
 		import.get_file()
 	);
-	if(command=="--exec")
-		vm.run(codegen.get_exec_code());
+	if(command=="--exec" || command=="--opcnt")
+		vm.run(codegen.get_exec_code(),command=="--opcnt");
 	else if(command=="--time")
 	{
 		clock_t begin=clock();
-		vm.run(codegen.get_exec_code());
+		vm.run(codegen.get_exec_code(),false);
 		std::cout<<"process exited after "<<((double)(clock()-begin))/CLOCKS_PER_SEC<<"s.\n";
 	}
 	vm.clear();
@@ -127,9 +128,10 @@ int main(int argc,const char* argv[])
 	}
 	else if(argc==3 &&
 		(!strcmp(argv[1],"--lex") ||
-		!strcmp(argv[1],"--ast") ||
+		!strcmp(argv[1],"--ast")  ||
 		!strcmp(argv[1],"--code") ||
 		!strcmp(argv[1],"--exec") ||
+		!strcmp(argv[1],"--opcnt")||
 		!strcmp(argv[1],"--time")))
 	{
 		file=argv[2];
diff --git a/nasal_codegen.h b/nasal_codegen.h
index 13cc5fe..df7824f 100644
--- a/nasal_codegen.h
+++ b/nasal_codegen.h
@@ -1276,13 +1276,17 @@ void nasal_codegen::print_op(int index)
 
 void nasal_codegen::print_byte_code()
 {
+    if(num_res_table.size())
+        std::cout<<".number"<<std::endl;
     for(auto& num:num_res_table)
-        std::cout<<".number "<<num<<'\n';
+        std::cout<<'\t'<<num<<'\n';
+    if(str_res_table.size())
+        std::cout<<".symbol"<<std::endl;
     for(auto& str:str_res_table)
     {
-        std::cout<<".symbol ";
+        std::cout<<'\t';
         raw_string(str);
-        std::cout<<'\n';
+        std::cout<<std::endl;
     }
     for(int i=0;i<exec_code.size();++i)
         print_op(i);
diff --git a/nasal_gc.h b/nasal_gc.h
index 34160c3..983d5e8 100644
--- a/nasal_gc.h
+++ b/nasal_gc.h
@@ -101,7 +101,8 @@ void nasal_vec::print()
         std::cout<<"[]";
         return;
     }
-    std::cout<<'[';  
+    ssize_t iter=0;
+    std::cout<<'[';
     for(auto i:elems)
     {
         switch(i->type)
@@ -113,7 +114,7 @@ void nasal_vec::print()
             case vm_hash: i->ptr.hash->print();      break;
             case vm_func: std::cout<<"func(..){..}"; break;
         }
-        std::cout<<",]"[i==elems.back()];
+        std::cout<<",]"[(++iter)==elems.size()];
     }
     return;
 }
diff --git a/nasal_vm.h b/nasal_vm.h
index c477f73..c98c715 100644
--- a/nasal_vm.h
+++ b/nasal_vm.h
@@ -108,7 +108,7 @@ public:
         std::vector<double>&,
         std::vector<std::string>&);
     void clear();
-    void run(std::vector<opcode>&);
+    void run(std::vector<opcode>&,bool);
 };
 
 void nasal_vm::init(
@@ -180,7 +180,7 @@ void nasal_vm::stackinfo(int limit)
         }
         if(same_cnt)
         {
-            printf("\t%p %d same value(s) ...\n",last_ptr,same_cnt);
+            printf("\t%p ...  | %d same value(s)\n",last_ptr,same_cnt);
             same_cnt=0;
         }
         last_ptr=stack_top[-i];
@@ -190,18 +190,18 @@ void nasal_vm::stackinfo(int limit)
         else
             switch(stack_top[-i]->type)
             {
-                case vm_nil:  printf("nil");break;
+                case vm_nil:  printf("nil  | gc.nil_addr");break;
                 case vm_num:  printf("num  | %lf",stack_top[-i]->ptr.num);break;
                 case vm_str:  printf("str  | ");raw_string(*stack_top[-i]->ptr.str);break;
-                case vm_func: printf("func | func(..){..}");break;
-                case vm_vec:  printf("vec  | ");stack_top[-i]->ptr.vec->print();break;
-                case vm_hash: printf("hash | ");stack_top[-i]->ptr.hash->print();break;
+                case vm_func: printf("func | func(%lu para){..}",stack_top[-i]->ptr.func->key_table.size());break;
+                case vm_vec:  printf("vec  | [%lu val]",stack_top[-i]->ptr.vec->elems.size());break;
+                case vm_hash: printf("hash | {%lu member}",stack_top[-i]->ptr.hash->elems.size());break;
                 default:      printf("unknown");break;
             }
         putchar('\n');
     }
     if(same_cnt)
-       printf("\t%p %d same value(s) ...\n",last_ptr,same_cnt);
+       printf("\t%p ...  | %d same value(s)\n",last_ptr,same_cnt);
     return;
 }
 void nasal_vm::die(std::string str)
@@ -221,7 +221,7 @@ void nasal_vm::stackoverflow()
     stackinfo(10);
     return;
 }
-bool nasal_vm::condition(nasal_val* val_addr)
+inline bool nasal_vm::condition(nasal_val* val_addr)
 {
     if(val_addr->type==vm_num)
         return val_addr->ptr.num;
@@ -965,9 +965,9 @@ inline void nasal_vm::opr_ret()
     stack_top[0]=stack_top[1];// rewrite nasal_func with returned value
     return;
 }
-void nasal_vm::run(std::vector<opcode>& exec)
+void nasal_vm::run(std::vector<opcode>& exec,bool op_cnt)
 {
-    //uint64_t count[op_ret+1]={0};
+    uint64_t count[op_ret+1]={0};
     void* opr_table[]=
     {
         &&nop,     &&intg,     &&intl,   &&offset,
@@ -1009,23 +1009,25 @@ nop:
     if(canary && canary!=(nasal_val*)0xffff)
         stackoverflow();
     // debug
-    // for(int i=0;i<15;++i)
-    // {
-    //     uint64_t maxnum=0,index=0;
-    //     for(int j=0;j<op_ret+1;++j)
-    //         if(count[j]>maxnum)
-    //         {
-    //             index=j;
-    //             maxnum=count[j];
-    //         }
-    //     std::cout<<code_table[index].name<<": "<<maxnum<<"\n";
-    //     count[index]=0;
-    // }
+    if(op_cnt)
+    {
+        std::cout<<std::endl;
+        for(int i=0;i<15;++i)
+        {
+            uint64_t maxnum=0,index=0;
+            for(int j=0;j<op_ret+1;++j)
+                if(count[j]>maxnum)
+                {
+                    index=j;
+                    maxnum=count[j];
+                }
+            std::cout<<code_table[index].name<<": "<<maxnum<<"\n";
+            count[index]=0;
+        }
+    }
     return;
-//#define exec_operand(op,num) {op();++count[num];if(!canary[0])goto *code[++pc];goto nop;}
-#define exec_operand(op,num) {op();if(!canary)goto *code[++pc];goto nop;}
-//#define exec_opnodie(op,num) {op();++count[num];goto *code[++pc];}
-#define exec_opnodie(op,num) {op();goto *code[++pc];}
+#define exec_operand(op,num) {op();++count[num];if(!canary)goto *code[++pc];goto nop;}
+#define exec_opnodie(op,num) {op();++count[num];goto *code[++pc];}
 
 intg:    exec_opnodie(opr_intg    ,op_intg    );
 intl:    exec_opnodie(opr_intl    ,op_intl    );
diff --git a/props.nas b/props.nas
index 0cc8399..80d2a0c 100644
--- a/props.nas
+++ b/props.nas
@@ -63,14 +63,14 @@ props.Node=
         foreach(var label;path)
             tmp=tmp.val[label];
         tmp.val=val;
-        if(typeof(val)=='string')
+        if(typeof(val)=='str')
         {
             if(val=='true' or val=='false')
                 tmp.type='BOOL';
             else
                 tmp.type='STRING';
         }
-        elsif(typeof(val)=='number')
+        elsif(typeof(val)=='num')
             tmp.type='DOUBLE';
         return;
     },
@@ -117,6 +117,11 @@ props.Node=
         if(typeof(me.val)=='hash')
         {
             var key=keys(me.val);
+            if(!size(key))
+            {
+                println("{}");
+                return;
+            }
             println('{');
             foreach(var k;key)
             {