diff --git a/README.md b/README.md
index dad99c2..f517ab4 100644
--- a/README.md
+++ b/README.md
@@ -904,7 +904,7 @@ nasal_ref builtin_print(std::vector<nasal_ref>& local,nasal_gc& gc)
 ```
 After that, register the built-in function's name(in nasal) and the function's pointer in this table:
 ```C++
-struct FUNC_TABLE
+struct func
 {
     const char* name;
     nasal_ref (*func)(std::vector<nasal_ref>&,nasal_gc&);
diff --git a/main.cpp b/main.cpp
index ab6a625..a58a054 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,24 +1,28 @@
 #include "nasal.h"
-
+#define VM_LEXINFO   1
+#define VM_ASTINFO   2
+#define VM_CODEINFO  4
+#define VM_EXECTIME  8
+#define VM_OPCALLNUM 16
+#define VM_EXEC      32
 void help_cmd()
 {
     std::cout
 #ifdef _WIN32
     <<"use command \'chcp 65001\' if want to use unicode.\n"
 #endif
-    <<"nasal [option]\n"
+    <<"nasal <option>\n"
     <<"option:\n"
     <<"    -h, --help    | get help.\n"
     <<"    -v, --version | get version of nasal interpreter.\n\n"
-    <<"nasal [file]\n"
+    <<"nasal <file>\n"
     <<"file:\n"
     <<"    input file name to execute script file.\n\n"
-    <<"nasal [option] [file]\n"
+    <<"nasal [options] <file>\n"
     <<"option:\n"
     <<"    -l, --lex     | view token info.\n"
     <<"    -a, --ast     | view abstract syntax tree.\n"
     <<"    -c, --code    | view bytecode.\n"
-    <<"    -e, --exec    | execute script file.\n"
     <<"    -t, --time    | execute and get the running time.\n"
     <<"    -o, --opcnt   | count operands while running.\n"
     <<"file:\n"
@@ -47,98 +51,94 @@ void die(const char* stage,const std::string& filename)
 {
     std::cout<<"["<<stage<<"] in <"<<filename<<">: error(s) occurred,stop.\n";
     std::exit(1);
-    return;
 }
 
-void execute(const std::string& file,const std::string& command)
+void cmderr()
+{
+    std::cout
+    <<"invalid argument(s).\n"
+    <<"use nasal -h to get help.\n";
+    std::exit(1);
+}
+
+void execute(const std::string& file,const uint16_t cmd)
 {
     nasal_lexer   lexer;
     nasal_parse   parse;
     nasal_import  import;
     nasal_codegen codegen;
     nasal_vm      vm;
-    lexer.openfile(file);
-    lexer.scanner();
-    if(lexer.get_error())
+    lexer.open(file);
+    lexer.scan();
+    if(lexer.err())
         die("lexer",file);
-    if(command=="--lex" || command=="-l")
-    {
-        lexer.print_token();
-        return;
-    }
-    parse.main_process(lexer.get_token_list());
-    if(parse.get_error())
+    if(cmd&VM_LEXINFO)
+        lexer.print();
+    parse.compile(lexer.get_tokens());
+    if(parse.err())
         die("parse",file);
-    if(command=="--ast" || command=="-a")
-    {
-        parse.get_root().print_ast(0);
-        return;
-    }
+    if(cmd&VM_ASTINFO)
+        parse.get_root().print(0);
     // first used file is itself
     import.link(parse.get_root(),file);
-    if(import.get_error())
+    if(import.err())
         die("import",file);
-    codegen.main_progress(import.get_root(),import.get_file());
-    if(codegen.get_error())
+    codegen.compile(import.get_root(),import.get_file());
+    if(codegen.err())
         die("code",file);
-    if(command=="--code" || command=="-c")
-    {
-        codegen.print_byte_code();
-        return;
-    }
+    if(cmd&VM_CODEINFO)
+        codegen.print();
     vm.init(
-        codegen.get_str_table(),
-        codegen.get_num_table(),
+        codegen.get_strs(),
+        codegen.get_nums(),
         import.get_file()
     );
-    if(command=="--exec" || command=="-e" || command=="--opcnt" || command=="-o")
-        vm.run(codegen.get_exec_code(),command=="--opcnt" || command=="-o");
-    else if(command=="--time" || command=="-t")
+    if(cmd&VM_EXECTIME)
     {
-        clock_t begin=clock();
-        vm.run(codegen.get_exec_code(),false);
-        std::cout<<"process exited after "<<((double)(clock()-begin))/CLOCKS_PER_SEC<<"s.\n";
+        clock_t t=clock();
+        vm.run(codegen.get_code(),cmd&VM_OPCALLNUM);
+        std::cout<<"process exited after "<<((double)(clock()-t))/CLOCKS_PER_SEC<<"s.\n";
     }
+    else if(cmd&VM_EXEC)
+        vm.run(codegen.get_code(),cmd&VM_OPCALLNUM);
     vm.clear();
     return;
 }
+
 int main(int argc,const char* argv[])
 {
-    std::string command,file;
+    std::string filename;
+    uint16_t cmd=0;
     if(argc==2 && (!strcmp(argv[1],"-v") || !strcmp(argv[1],"--version")))
         logo();
     else if(argc==2 && (!strcmp(argv[1],"-h") || !strcmp(argv[1],"--help")))
         help_cmd();
     else if(argc==2 && argv[1][0]!='-')
+        cmd|=VM_EXEC;
+    else if(argc>=3)
     {
-        file=argv[1];
-        command="-e";
-        execute(file,command);
-    }
-    else if(argc==3 &&
-        (!strcmp(argv[1],"--lex") ||
-        !strcmp(argv[1],"-l")     ||
-        !strcmp(argv[1],"--ast")  ||
-        !strcmp(argv[1],"-a")     ||
-        !strcmp(argv[1],"--code") ||
-        !strcmp(argv[1],"-c")     ||
-        !strcmp(argv[1],"--exec") ||
-        !strcmp(argv[1],"-e")     ||
-        !strcmp(argv[1],"--opcnt")||
-        !strcmp(argv[1],"-o")     ||
-        !strcmp(argv[1],"--time") ||
-        !strcmp(argv[1],"-t")))
-    {
-        file=argv[2];
-        command=argv[1];
-        execute(file,command);
+        for(int i=1;i<argc-1;++i)
+        {
+            std::string s(argv[i]);
+            if(s=="--lex" || s=="-l")
+                cmd|=VM_LEXINFO;
+            else if(s=="--ast" || s=="-a")
+                cmd|=VM_ASTINFO;
+            else if(s=="--code" || s=="-c")
+                cmd|=VM_CODEINFO;
+            else if(s=="--opcnt" || s=="-o")
+                cmd|=VM_OPCALLNUM|VM_EXEC;
+            else if(s=="--time" || s=="-t")
+                cmd|=VM_EXECTIME;
+            else
+                cmderr();
+        }
     }
     else
-    {
-        std::cout
-        <<"invalid argument(s).\n"
-        <<"use nasal -h to get help.\n";
-        std::exit(1);
-    }
+        cmderr();
+    if(argv[argc-1][0]=='-')
+        cmderr();
+    if(cmd)
+        execute(argv[argc-1],cmd);
     return 0;
 }
\ No newline at end of file
diff --git a/nasal.h b/nasal.h
index b38a98d..ddfffb1 100644
--- a/nasal.h
+++ b/nasal.h
@@ -1,6 +1,5 @@
 #ifndef __NASAL_H__
 #define __NASAL_H__
-
 #pragma GCC optimize(2)
 
 #include <stdint.h>
@@ -108,22 +107,23 @@ double str2num(const char* str)
 /*
     show raw string
 */
-void raw_string(const std::string& str)
+std::string raw_string(const std::string& str)
 {
+    std::string ret("");
     for(auto i:str)
         switch(i)
         {
-            case '\a': std::cout<<"\\a";break;
-            case '\b': std::cout<<"\\b";break;
-            case '\f': std::cout<<"\\f";break;
-            case '\n': std::cout<<"\\n";break;
-            case '\r': std::cout<<"\\r";break;
-            case '\t': std::cout<<"\\t";break;
-            case '\v': std::cout<<"\\v";break;
-            case '\0': std::cout<<"\\0";break;
-            default:   std::cout<<i;    break;
+            case '\a': ret+="\\a";break;
+            case '\b': ret+="\\b";break;
+            case '\f': ret+="\\f";break;
+            case '\n': ret+="\\n";break;
+            case '\r': ret+="\\r";break;
+            case '\t': ret+="\\t";break;
+            case '\v': ret+="\\v";break;
+            case '\0': ret+="\\0";break;
+            default:   ret+=i;    break;
         }
-    return;
+    return ret;
 }
 #include "nasal_lexer.h"
 #include "nasal_ast.h"
diff --git a/nasal_ast.h b/nasal_ast.h
index c23ff38..1b2077b 100644
--- a/nasal_ast.h
+++ b/nasal_ast.h
@@ -50,36 +50,37 @@ const char* ast_name[]=
 class nasal_ast
 {
 private:
-    int         line;
-    int         type;
+    uint32_t    line;
+    uint32_t    type;
     double      num;
     std::string str;
     std::vector<nasal_ast> children;
 public:
     nasal_ast(){line=0;type=ast_null;}
-    nasal_ast(const int l,const int t){line=l;type=t;}
+    nasal_ast(const uint32_t l,const uint32_t t){line=l;type=t;}
     nasal_ast(const nasal_ast&);
     nasal_ast(nasal_ast&&);
     nasal_ast& operator=(const nasal_ast&);
     nasal_ast& operator=(nasal_ast&&);
-    void   print_ast(const int);
+    void   print(const int);
     void   clear();
     void   add_child(nasal_ast&& ast){children.push_back(std::move(ast));}
     void   add_child(const nasal_ast& ast){children.push_back(ast);}
-    void   set_line(const int l){line=l;}
-    void   set_type(const int t){type=t;}
+    void   set_line(const uint32_t l){line=l;}
+    void   set_type(const uint32_t t){type=t;}
     void   set_str(const std::string& s){str=s;}
     void   set_num(const double n){num=n;}
-    int    get_line(){return line;}
-    int    get_type(){return type;}
-    double get_num() {return num;}
-    std::string& get_str(){return str;}
+
+    uint32_t     get_line(){return line;}
+    uint32_t     get_type(){return type;}
+    double       get_num() {return num;}
+    std::string& get_str() {return str;}
     std::vector<nasal_ast>& get_children(){return children;}
 
-    int    get_line() const {return line;}
-    int    get_type() const {return type;}
-    double get_num()  const {return num;}
-    const std::string& get_str() const {return str;}
+    uint32_t           get_line() const {return line;}
+    uint32_t           get_type() const {return type;}
+    double             get_num()  const {return num;}
+    const std::string& get_str()  const {return str;}
     const std::vector<nasal_ast>& get_children() const {return children;}
 };
 
@@ -133,21 +134,18 @@ void nasal_ast::clear()
     return;
 }
 
-void nasal_ast::print_ast(const int depth)
+void nasal_ast::print(const int depth)
 {
     for(int i=0;i<depth;++i)
         std::cout<<"|  ";
     std::cout<<ast_name[type];
     if(type==ast_str || type==ast_id || type==ast_default_arg || type==ast_dynamic_id || type==ast_callh)
-    {
-        std::cout<<":";
-        raw_string(str);
-    }
+        std::cout<<":"<<raw_string(str);
     else if(type==ast_num || type==ast_file)
         std::cout<<":"<<num;
     std::cout<<'\n';
     for(auto& i:children)
-        i.print_ast(depth+1);
+        i.print(depth+1);
     return;
 }
 
diff --git a/nasal_builtin.h b/nasal_builtin.h
index 6ffbe64..e017cad 100644
--- a/nasal_builtin.h
+++ b/nasal_builtin.h
@@ -62,8 +62,8 @@ nasal_ref builtin_err(const char* func_name,std::string info)
 }
 
 // register builtin function's name and it's address here in this table below
-// this table must end with {"",nullptr}
-struct FUNC_TABLE
+// this table must end with {nullptr,nullptr}
+struct func
 {
     const char* name;
     nasal_ref (*func)(std::vector<nasal_ref>&,nasal_gc&);
@@ -123,7 +123,7 @@ nasal_ref builtin_print(std::vector<nasal_ref>& local,nasal_gc& gc)
     for(auto i:vec.vec()->elems)
         switch(i.type)
         {
-            case vm_none: std::cout<<"undefined";      break;
+            case vm_none: std::cout<<"null";           break;
             case vm_nil:  std::cout<<"nil";            break;
             case vm_num:  std::cout<<i.num();          break;
             case vm_str:  std::cout<<*i.str();         break;
diff --git a/nasal_codegen.h b/nasal_codegen.h
index 0b3b5e8..7d6ee9d 100644
--- a/nasal_codegen.h
+++ b/nasal_codegen.h
@@ -255,13 +255,13 @@ private:
     void block_gen(const nasal_ast&);
     void ret_gen(const nasal_ast&);
 public:
-    uint32_t                  get_error(){return error;}
-    void                      main_progress(const nasal_ast&,const std::vector<std::string>&);
+    uint32_t                  err(){return error;}
+    void                      compile(const nasal_ast&,const std::vector<std::string>&);
     void                      print_op(uint32_t);
-    void                      print_byte_code();
-    std::vector<std::string>& get_str_table(){return str_res_table;}
-    std::vector<double>&      get_num_table(){return num_res_table;}
-    std::vector<opcode>&      get_exec_code(){return exec_code;}
+    void                      print();
+    std::vector<std::string>& get_strs(){return str_res_table;}
+    std::vector<double>&      get_nums(){return num_res_table;}
+    std::vector<opcode>&      get_code(){return exec_code;}
 };
 
 void nasal_codegen::die(const std::string info,const int line)
@@ -631,7 +631,7 @@ void nasal_codegen::mcall(const nasal_ast& ast)
 void nasal_codegen::mcall_id(const nasal_ast& ast)
 {
     const std::string& str=ast.get_str();
-    for(int i=0;builtin_func[i].name;++i)
+    for(uint32_t i=0;builtin_func[i].name;++i)
         if(builtin_func[i].name==str)
         {
             die("cannot change builtin function.",ast.get_line());
@@ -1213,7 +1213,7 @@ void nasal_codegen::ret_gen(const nasal_ast& ast)
     return;
 }
 
-void nasal_codegen::main_progress(const nasal_ast& ast,const std::vector<std::string>& files)
+void nasal_codegen::compile(const nasal_ast& ast,const std::vector<std::string>& files)
 {
     error=0;
     in_foreach=0;
@@ -1326,25 +1326,19 @@ void nasal_codegen::print_op(uint32_t index)
         case op_lnkc:case op_lnkeqc:
         case op_callh:case op_mcallh:
         case op_para:case op_defpara:case op_dynpara:
-            printf("0x%x (\"",code.num);
-            raw_string(str_res_table[code.num]);
-            printf("\")\n");
+            printf("0x%x (\"%s\")\n",code.num,raw_string(str_res_table[code.num]).c_str());
             break;
         default:printf("\n");break;
     }
     return;
 }
 
-void nasal_codegen::print_byte_code()
+void nasal_codegen::print()
 {
     for(auto num:num_res_table)
         std::cout<<".number "<<num<<'\n';
     for(auto& str:str_res_table)
-    {
-        std::cout<<".symbol \"";
-        raw_string(str);
-        std::cout<<"\"\n";
-    }
+        std::cout<<".symbol \""<<raw_string(str)<<"\"\n";
     for(uint32_t i=0;i<exec_code.size();++i)
         print_op(i);
     return;
diff --git a/nasal_gc.h b/nasal_gc.h
index 083ed1b..0ca6d40 100644
--- a/nasal_gc.h
+++ b/nasal_gc.h
@@ -3,11 +3,11 @@
 
 enum nasal_type
 {
-    // none-gc object
+    /* none-gc object */
     vm_none=0,
     vm_nil,
     vm_num,
-    // gc object
+    /* gc object */
     vm_str,
     vm_func,
     vm_vec,
@@ -17,19 +17,19 @@ enum nasal_type
 };
 
 // change parameters here to make your own efficient gc
-// better set bigger number on vm_num and vm_vec
+// better set bigger number on vm_vec
 const uint32_t increment[vm_type_size]=
 {
-    // none-gc object
+    /* none-gc object */
     0,    // vm_none, error type
     0,    // vm_nil
     0,    // vm_num
-    // gc object
+    /* gc object */
     2048, // vm_str
     1024, // vm_func
     8192, // vm_vec
     512,  // vm_hash
-    0     // vm_obj
+    128   // vm_obj
 };
 
 // declaration of nasal value type
@@ -83,7 +83,7 @@ struct nasal_ref// 16 bytes
     inline nasal_vec*   vec ();
     inline nasal_hash*  hash();
     inline nasal_func*  func();
-    inline void*        obj ();
+    inline void*&       obj ();
 };
 
 struct nasal_vec// 24 bytes
@@ -282,6 +282,7 @@ nasal_val::nasal_val(uint8_t val_type)
         case vm_vec:  ptr.vec=new nasal_vec;   break;
         case vm_hash: ptr.hash=new nasal_hash; break;
         case vm_func: ptr.func=new nasal_func; break;
+        case vm_obj:  ptr.obj=nullptr;         break;
     }
     return;
 }
@@ -293,7 +294,12 @@ nasal_val::~nasal_val()
         case vm_vec:  delete ptr.vec;  break;
         case vm_hash: delete ptr.hash; break;
         case vm_func: delete ptr.func; break;
+        case vm_obj:
+            if(ptr.obj)
+                free(ptr.obj);
+            break;
     }
+    ptr.obj=nullptr;
     type=vm_nil;
     return;
 }
@@ -313,12 +319,12 @@ std::string nasal_ref::to_string()
         return std::to_string(num());
     return "";
 }
-inline double&      nasal_ref::num (){return value.num;}
-inline std::string* nasal_ref::str (){return value.gcobj->ptr.str;}
-inline nasal_vec*   nasal_ref::vec (){return value.gcobj->ptr.vec;}
+inline double&      nasal_ref::num (){return value.num;            }
+inline std::string* nasal_ref::str (){return value.gcobj->ptr.str; }
+inline nasal_vec*   nasal_ref::vec (){return value.gcobj->ptr.vec; }
 inline nasal_hash*  nasal_ref::hash(){return value.gcobj->ptr.hash;}
 inline nasal_func*  nasal_ref::func(){return value.gcobj->ptr.func;}
-inline void*        nasal_ref::obj (){return value.gcobj->ptr.obj;}
+inline void*&       nasal_ref::obj (){return value.gcobj->ptr.obj; }
 
 struct nasal_gc
 {
@@ -326,7 +332,7 @@ struct nasal_gc
     nasal_ref               zero;               // reserved address of nasal_val,type vm_num, 0
     nasal_ref               one;                // reserved address of nasal_val,type vm_num, 1
     nasal_ref               nil;                // reserved address of nasal_val,type vm_nil
-    nasal_ref               val_stack[STACK_MAX_DEPTH+1];// 1 reserved to avoid stack overflow, stack grows 1 each time
+    nasal_ref               val_stack[STACK_MAX_DEPTH+1];// 1 reserved to avoid stack overflow
     nasal_ref*              stack_top;               // stack top
     std::vector<nasal_ref>  str_addrs;               // reserved address for const vm_str
     std::vector<nasal_val*> memory;                  // gc memory
@@ -386,6 +392,11 @@ void nasal_gc::sweep()
                 case vm_vec: i->ptr.vec->elems.clear(); break;
                 case vm_hash:i->ptr.hash->elems.clear();break;
                 case vm_func:i->ptr.func->clear();      break;
+                case vm_obj:
+                    if(i->ptr.obj)
+                        free(i->ptr.obj);
+                    i->ptr.obj=nullptr;
+                    break;
             }
             free_list[i->type].push(i);
             i->mark=GC_COLLECTED;
@@ -429,7 +440,6 @@ void nasal_gc::gc_clear()
         while(!free_list[i].empty())
             free_list[i].pop();
     local.clear();
-
     for(auto& i:str_addrs)
         delete i.value.gcobj;
     str_addrs.clear();
diff --git a/nasal_import.h b/nasal_import.h
index 4bfa1e3..f3be9dc 100644
--- a/nasal_import.h
+++ b/nasal_import.h
@@ -4,7 +4,7 @@
 class nasal_import
 {
 private:
-    int                      error;
+    uint32_t                 error;
     nasal_lexer              import_lex;
     nasal_parse              import_par;
     nasal_ast                import_ast;
@@ -16,19 +16,16 @@ private:
     nasal_ast file_import(nasal_ast&);
     nasal_ast load(nasal_ast&,uint16_t);
 public:
-    const int get_error(){return error;}
+    uint32_t  err(){return error;}
     void      link(nasal_ast&,const std::string&);
-    const nasal_ast& 
-        get_root(){return import_ast;}
-    const std::vector<std::string>& 
-        get_file(){return filename_table;}
+    const nasal_ast& get_root(){return import_ast;}
+    const std::vector<std::string>& get_file(){return filename_table;}
 };
 
 void nasal_import::die(const std::string& filename,const char* error_stage)
 {
     ++error;
     std::cout<<"[import] in <\""<<filename<<"\">: error(s) occurred in "<<error_stage<<".\n";
-    return;
 }
 
 bool nasal_import::check_import(const nasal_ast& node)
@@ -69,7 +66,6 @@ void nasal_import::linker(nasal_ast& root,nasal_ast&& add_root)
     // add children of add_root to the back of root
     for(auto& i:add_root.get_children())
         root.add_child(std::move(i));
-    return;
 }
 
 nasal_ast nasal_import::file_import(nasal_ast& node)
@@ -86,15 +82,15 @@ nasal_ast nasal_import::file_import(nasal_ast& node)
         return tmp;
     
     // start importing...
-    import_lex.openfile(filename);
-    import_lex.scanner();
-    if(import_lex.get_error())
+    import_lex.open(filename);
+    import_lex.scan();
+    if(import_lex.err())
     {
         die(filename,"lexer");
         return tmp;
     }
-    import_par.main_process(import_lex.get_token_list());
-    if(import_par.get_error())
+    import_par.compile(import_lex.get_tokens());
+    if(import_par.err())
     {
         die(filename,"parser");
         return tmp;
@@ -128,7 +124,6 @@ void nasal_import::link(nasal_ast& root,const std::string& self)
     // scan root and import files,then generate a new ast and return to import_ast
     // the main file's index is 0
     import_ast=load(root,0);
-    return;
 }
 
 #endif
\ No newline at end of file
diff --git a/nasal_lexer.h b/nasal_lexer.h
index 9d1e5ac..5d03087 100644
--- a/nasal_lexer.h
+++ b/nasal_lexer.h
@@ -87,36 +87,36 @@ struct
 
 struct token
 {
-    int line;
-    int type;
+    uint32_t line;
+    uint32_t type;
     std::string str;
-    token(int l=0,int t=tok_null,std::string s=""){line=l;type=t;str=s;}
+    token(uint32_t l=0,uint32_t t=tok_null,std::string s=""){line=l;type=t;str=s;}
 };
 
 class nasal_lexer
 {
 private:
-    int error;
-    int res_size;
-    int line;
-    int ptr;
+    uint32_t    error;
+    uint32_t    line;
+    uint32_t    ptr;
+    size_t      res_size;
     std::string line_code;
     std::string res;
     std::vector<token> token_list;
-    int  get_tok_type(const std::string&);
+    uint32_t get_type(const std::string&);
     void die(const char*);
     std::string id_gen();
     std::string num_gen();
     std::string str_gen();
 public:
-    void openfile(const std::string&);
-    void scanner();
-    void print_token();
-    int  get_error(){return error;}
-    std::vector<token>& get_token_list(){return token_list;}
+    void open(const std::string&);
+    void scan();
+    void print();
+    uint32_t err(){return error;}
+    const std::vector<token>& get_tokens(){return token_list;}
 };
 
-void nasal_lexer::openfile(const std::string& filename)
+void nasal_lexer::open(const std::string& filename)
 {
     error=0;
     res.clear();
@@ -137,7 +137,7 @@ void nasal_lexer::openfile(const std::string& filename)
     return;
 }
 
-int nasal_lexer::get_tok_type(const std::string& tk_str)
+uint32_t nasal_lexer::get_type(const std::string& tk_str)
 {
     for(int i=0;token_table[i].str;++i)
         if(tk_str==token_table[i].str)
@@ -272,7 +272,7 @@ std::string nasal_lexer::str_gen()
     return token_str;
 }
 
-void nasal_lexer::scanner()
+void nasal_lexer::scan()
 {
     token_list.clear();
     line=1;
@@ -297,7 +297,7 @@ void nasal_lexer::scanner()
         if(IS_IDENTIFIER(res[ptr]))
         {
             token_str=id_gen();
-            token_list.push_back({line,get_tok_type(token_str),token_str});
+            token_list.push_back({line,get_type(token_str),token_str});
             if(!token_list.back().type)
                 token_list.back().type=tok_id;
         }
@@ -309,7 +309,7 @@ void nasal_lexer::scanner()
         {
             token_str=res[ptr];
             line_code+=res[ptr];
-            int type=get_tok_type(token_str);
+            uint32_t type=get_type(token_str);
             if(!type)
                 die("incorrect operator.");
             token_list.push_back({line,type,token_str});
@@ -328,7 +328,7 @@ void nasal_lexer::scanner()
                 ++ptr;
             }
             line_code+=token_str;
-            token_list.push_back({line,get_tok_type(token_str),token_str});
+            token_list.push_back({line,get_type(token_str),token_str});
         }
         else if(IS_CALC_OPERATOR(res[ptr]))
         {
@@ -337,7 +337,7 @@ void nasal_lexer::scanner()
             if(ptr<res_size && res[ptr]=='=')
                 token_str+=res[ptr++];
             line_code+=token_str;
-            token_list.push_back({line,get_tok_type(token_str),token_str});
+            token_list.push_back({line,get_type(token_str),token_str});
         }
         else if(IS_NOTE(res[ptr]))// avoid note, after this process ptr will point to a '\n', so next loop line counter+1
             while(++ptr<res_size && res[ptr]!='\n');
@@ -352,7 +352,7 @@ void nasal_lexer::scanner()
     return;
 }
 
-void nasal_lexer::print_token()
+void nasal_lexer::print()
 {
     for(auto& tok:token_list)
         std::cout<<"("<<tok.line<<" | "<<tok.str<<")\n";
diff --git a/nasal_parse.h b/nasal_parse.h
index 33b28be..da2533d 100644
--- a/nasal_parse.h
+++ b/nasal_parse.h
@@ -42,7 +42,7 @@ class nasal_parse
 #define is_call(type) ((type)==tok_lcurve || (type)==tok_lbracket || (type)==tok_dot)
 private:
     int ptr;
-    int error;
+    uint32_t error;
     nasal_ast root;
     std::vector<token> tok_list;
     std::vector<token> error_token;
@@ -99,11 +99,11 @@ private:
     nasal_ast break_expr();
     nasal_ast ret_expr();
 public:
-    int get_error(){return error;}
-    void main_process(std::vector<token>&);
+    uint32_t   err(){return error;}
+    void       compile(const std::vector<token>&);
     nasal_ast& get_root(){return root;}
 };
-void nasal_parse::main_process(std::vector<token>& toks)
+void nasal_parse::compile(const std::vector<token>& toks)
 {
     tok_list=toks;
     ptr=in_function=in_loop=error=0;
diff --git a/nasal_vm.h b/nasal_vm.h
index 07a1bf3..8d0958c 100644
--- a/nasal_vm.h
+++ b/nasal_vm.h
@@ -193,20 +193,17 @@ void nasal_vm::stackinfo(const uint32_t limit)
         }
         last_ptr=stack_top[0];
         const nasal_val* ptr=stack_top[0].value.gcobj;
-        putchar('\t');
         switch(stack_top[0].type)
         {
-            case vm_none: printf("null |");break;
-            case vm_nil:  printf("nil  |");break;
-            case vm_num:  printf("num  | %lf",stack_top[0].num());break;
-            case vm_str:  printf("str  | <%p> ",ptr);raw_string(*stack_top[0].str());break;
-            case vm_func: printf("func | <%p> func{entry=0x%x}",ptr,stack_top[0].func()->entry);break;
-            case vm_vec:  printf("vec  | <%p> [%lu val]",ptr,stack_top[0].vec()->elems.size());break;
-            case vm_hash: printf("hash | <%p> {%lu member}",ptr,stack_top[0].hash()->elems.size());break;
-            case vm_obj:  printf("obj  | <%p>",ptr);break;
-            default:      printf("unknown");break;
+            case vm_none: printf("\tnull |\n");break;
+            case vm_nil:  printf("\tnil  |\n");break;
+            case vm_num:  printf("\tnum  | %lf\n",stack_top[0].num());break;
+            case vm_str:  printf("\tstr  | <%p> %s\n",ptr,raw_string(*stack_top[0].str()).c_str());break;
+            case vm_func: printf("\tfunc | <%p> func{entry=0x%x}\n",ptr,stack_top[0].func()->entry);break;
+            case vm_vec:  printf("\tvec  | <%p> [%lu val]\n",ptr,stack_top[0].vec()->elems.size());break;
+            case vm_hash: printf("\thash | <%p> {%lu member}\n",ptr,stack_top[0].hash()->elems.size());break;
+            case vm_obj:  printf("\tobj  | <%p>\n",ptr);break;
         }
-        putchar('\n');
     }
     if(same_cnt)
        printf("\t...  | %d same value(s)\n",same_cnt);
@@ -839,7 +836,9 @@ inline void nasal_vm::opr_ret()
     pc=ret.top();ret.pop(); // fetch pc
     return;
 }
-void nasal_vm::run(const std::vector<opcode>& exec,const bool op_cnt)
+void nasal_vm::run(
+    const std::vector<opcode>& exec,
+    const bool op_cnt)
 {
     uint64_t count[op_exit+1]={0};
     const void* opr_table[]=
@@ -865,7 +864,6 @@ void nasal_vm::run(const std::vector<opcode>& exec,const bool op_cnt)
         &&mcallg,  &&mcalll,   &&mupval, &&mcallv,
         &&mcallh,  &&ret,      &&vmexit
     };
-    
     bytecode=exec;
     std::vector<const void*> code;
     for(auto& i:exec)
diff --git a/test/hexdump.nas b/test/hexdump.nas
index 3115dcb..2c554a8 100644
--- a/test/hexdump.nas
+++ b/test/hexdump.nas
@@ -16,8 +16,7 @@ foreach(var i;hex_num)
         append(hex,i~j);
 
 # read file
-var s=func()
-{
+var s=func(){
     var filename=[
         "nasal.h",
         "main.cpp",
@@ -43,49 +42,45 @@ var cnt=0;
 var hex_index=[0,0,0,0];
 
 # print binary in text format
-var textprint=func(index)
-{
-    print(' |');
+var textprint=func(index){
+    var info='';
     for(var i=index-cnt;i<index;i+=1)
-        print((0<=s[i] and s[i]<32)?'.':chr(s[i]));
+        info~=(0<=s[i] and s[i]<32)?'.':chr(s[i]);
     for(var i=cnt;i<16;i+=1)
-        print('.');
-    print('|\n');
+        info~='.';
+    return ' |'~info~'|\n';
 }
 
 # print index
-var indexprint=func(index)
-{
-    forindex(var i;hex_index)
-    {
+var indexprint=func(index){
+    forindex(var i;hex_index){
         hex_index[i]=index-int(index/256)*256;
         index=int(index/256);
     }
+    var info='';
     for(var i=3;i>=0;i-=1)
-        print(hex[hex_index[i]]);
-    print('  ');
-    return;
+        info~=hex[hex_index[i]];
+    return info~'  ';
 }
 
 # main
-func()
-{
-    indexprint(0);
-    for(var i=0;i<size(s);i+=1)
-    {
+func(){
+    var info=indexprint(0);
+    for(var i=0;i<size(s);i+=1){
         if(cnt==16){
-            textprint(i);
+            info~=textprint(i);
+            print(info);
             cnt=0;
-            indexprint(i);
-        }elsif(cnt==8){
-            print(' ');
-        }
+            info=indexprint(i);
+        }elsif(cnt==8)
+            info~=' ';
         cnt+=1;
-        print(hex[s[i]],' ');
+        info~=hex[s[i]]~' ';
     }
     for(var l=cnt;l<16;l+=1)
-        print('   ');
+        info~='   ';
     if(cnt<=8)
-        print(' ');
-    textprint(i);
+        info~=' ';
+    info~=textprint(i);
+    print(info);
 }();
\ No newline at end of file