diff --git a/README.md b/README.md
index a90f40c..f5a72e8 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,6 @@
 
 <img src="./doc/pic/header.png" style="width:600px"></img>
 
-![GitHub code size](https://img.shields.io/github/languages/code-size/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 ![GitHub release(latest by date)](https://img.shields.io/github/v/release/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 [![license](https://img.shields.io/badge/license-GPLv2-green?style=flat-square&logo=github)](./LICENSE)
 ![downloads](https://img.shields.io/github/downloads/ValKmjolnir/Nasal-Interpreter/total.svg?style=flat-square&logo=github)
diff --git a/doc/README_zh.md b/doc/README_zh.md
index 1e2a96b..2f655e9 100644
--- a/doc/README_zh.md
+++ b/doc/README_zh.md
@@ -2,7 +2,6 @@
 
 <img src="../doc/pic/header.png" style="width:600px"></img>
 
-![GitHub code size](https://img.shields.io/github/languages/code-size/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 ![GitHub release(latest by date)](https://img.shields.io/github/v/release/ValKmjolnir/Nasal-Interpreter?style=flat-square&logo=github)
 [![license](https://img.shields.io/badge/license-GPLv2-green?style=flat-square&logo=github)](../LICENSE)
 ![downloads](https://img.shields.io/github/downloads/ValKmjolnir/Nasal-Interpreter/total.svg?style=flat-square&logo=github)
diff --git a/module/fib.cpp b/module/fib.cpp
index 68e7264..d618a37 100644
--- a/module/fib.cpp
+++ b/module/fib.cpp
@@ -53,7 +53,9 @@ struct ghost_obj {
 void ghost_for_test_destructor(void* ptr) {
     std::cout << "ghost_for_test::destructor (0x";
     std::cout << std::hex << reinterpret_cast<u64>(ptr) << std::dec << ") {\n";
+
     delete static_cast<ghost_obj*>(ptr);
+
     std::cout << "    delete 0x" << std::hex;
     std::cout << reinterpret_cast<u64>(ptr) << std::dec << ";\n";
     std::cout << "}\n";
@@ -62,7 +64,9 @@ void ghost_for_test_destructor(void* ptr) {
 void ghost_for_test_gc_marker(void* ptr, std::vector<var>* bfs_queue) {
     std::cout << "ghost_for_test::mark (0x";
     std::cout << std::hex << reinterpret_cast<u64>(ptr) << std::dec << ") {\n";
+
     bfs_queue->push_back(static_cast<ghost_obj*>(ptr)->test_string);
+
     std::cout << "    mark 0x" << std::hex;
     std::cout << reinterpret_cast<u64>(ptr) << std::dec << "->test_string;\n";
     std::cout << "}\n";
@@ -86,8 +90,10 @@ var set_new_ghost(var* args, usize size, gc* ngc) {
         return nil;
     }
     f64 num = args[1].num();
+
     reinterpret_cast<ghost_obj*>(res.ghost().pointer)->number = static_cast<u32>(num);
     std::cout << "set_new_ghost: successfully set ghost.number = " << num << "\n";
+
     reinterpret_cast<ghost_obj*>(res.ghost().pointer)->test_string = ngc->newstr("just for test");
     std::cout << "set_new_ghost: successfully set ghost.test_string = just for test\n";
     return nil;
diff --git a/src/ast_dumper.h b/src/ast_dumper.h
index e20f5c4..2049044 100644
--- a/src/ast_dumper.h
+++ b/src/ast_dumper.h
@@ -35,8 +35,7 @@ private:
     std::string format_location(const span& location) {
         std::stringstream ss;
         ss << " -> ";
-        ss << location.file << ":";
-        ss << location.begin_line << ":" << location.begin_column + 1;
+        location.dump_begin(ss);
         ss << "\n";
         return ss.str();
     }
diff --git a/src/nasal_ast.h b/src/nasal_ast.h
index 2d2a88c..3913ff9 100644
--- a/src/nasal_ast.h
+++ b/src/nasal_ast.h
@@ -8,7 +8,7 @@
 
 namespace nasal {
 
-enum class expr_type: u32 {
+enum class expr_type {
     ast_null = 0,    // null node
     ast_use,         // use statement
     ast_block,       // code block 
@@ -65,13 +65,13 @@ public:
     expr(const span& location, expr_type node_type):
         nd_loc(location), nd_type(node_type) {}
     virtual ~expr() = default;
-    void set_begin(u32 line, u32 column) {
+    void set_begin(u64 line, u64 column) {
         nd_loc.begin_line = line;
         nd_loc.begin_column = column;
     }
-    const span& get_location() const {return nd_loc;}
-    const u32 get_line() const {return nd_loc.begin_line;}
-    expr_type get_type() const {return nd_type;}
+    const auto& get_location() const { return nd_loc; }
+    const auto get_line() const { return nd_loc.begin_line; }
+    auto get_type() const { return nd_type; }
     void update_location(const span& location) {
         nd_loc.end_line = location.end_line;
         nd_loc.end_column = location.end_column;
diff --git a/src/nasal_dbg.cpp b/src/nasal_dbg.cpp
index 38c9e39..0975d3b 100644
--- a/src/nasal_dbg.cpp
+++ b/src/nasal_dbg.cpp
@@ -260,7 +260,7 @@ void dbg::run(
     std::vector<u32> code;
     std::vector<u16> code_file_index;
     std::vector<u32> code_line;
-    for(auto& i : gen.codes()) {
+    for(const auto& i : gen.codes()) {
         code.push_back(i.op);
         code_file_index.push_back(i.fidx);
         code_line.push_back(i.line);
diff --git a/src/nasal_err.cpp b/src/nasal_err.cpp
index 4f201ac..42a71d3 100644
--- a/src/nasal_err.cpp
+++ b/src/nasal_err.cpp
@@ -127,15 +127,15 @@ void error::err(
 
     ++cnt;
 
-    std::cerr
-    << red << stage << ": " << white << info << reset << "\n" << cyan << "  --> "
-    << red << loc.file << ":" << loc.begin_line << ":" << loc.begin_column+1
-    << reset << "\n";
+    std::cerr << red << stage << ": " << white << info << reset << "\n";
+    std::cerr << cyan << "  --> " << red;
+    loc.dump_begin(std::cerr);
+    std::cerr << reset << "\n";
 
     const usize maxlen = std::to_string(loc.end_line).length();
     const std::string iden = identation(maxlen);
 
-    for(u32 line = loc.begin_line; line<=loc.end_line; ++line) {
+    for(u64 line = loc.begin_line; line<=loc.end_line; ++line) {
         // skip line 0
         if (!line) {
             continue;
@@ -164,25 +164,25 @@ void error::err(
         // output underline
         std::cerr << cyan << iden << " | " << reset;
         if (loc.begin_line==loc.end_line) {
-            for(u32 i = 0; i<loc.begin_column; ++i) {
+            for(u64 i = 0; i<loc.begin_column; ++i) {
                 std::cerr << char(" \t"[code[i]=='\t']);
             }
-            for(u32 i = loc.begin_column; i<loc.end_column; ++i) {
+            for(u64 i = loc.begin_column; i<loc.end_column; ++i) {
                 std::cerr << red << (code[i]=='\t'? "^^^^":"^") << reset;
             }
         } else if (line==loc.begin_line) {
-            for(u32 i = 0; i<loc.begin_column; ++i) {
+            for(u64 i = 0; i<loc.begin_column; ++i) {
                 std::cerr << char(" \t"[code[i]=='\t']);
             }
-            for(u32 i = loc.begin_column; i<code.size(); ++i) {
+            for(u64 i = loc.begin_column; i<code.size(); ++i) {
                 std::cerr << red << (code[i]=='\t'? "^^^^":"^") << reset;
             }
         } else if (loc.begin_line<line && line<loc.end_line) {
-            for(u32 i = 0; i<code.size(); ++i) {
+            for(u64 i = 0; i<code.size(); ++i) {
                 std::cerr << red << (code[i]=='\t'? "^^^^":"^");
             }
         } else {
-            for(u32 i = 0; i<loc.end_column; ++i) {
+            for(u64 i = 0; i<loc.end_column; ++i) {
                 std::cerr << red << (code[i]=='\t'? "^^^^":"^");
             }
         }
diff --git a/src/nasal_err.h b/src/nasal_err.h
index 3aec9bf..a1cdf32 100644
--- a/src/nasal_err.h
+++ b/src/nasal_err.h
@@ -11,11 +11,15 @@
 namespace nasal {
 
 struct span {
-    u32 begin_line;
-    u32 begin_column;
-    u32 end_line;
-    u32 end_column;
+    u64 begin_line;
+    u64 begin_column;
+    u64 end_line;
+    u64 end_column;
     std::string file;
+
+    void dump_begin(std::ostream& out) const {
+        out << file << ":" << begin_line << ":" << begin_column + 1;
+    }
 };
 
 std::ostream& back_white(std::ostream&);
@@ -46,7 +50,7 @@ private:
     std::string identation(usize len) {
         return std::string(len, ' ');
     }
-    std::string leftpad(u32 num, usize len) {
+    std::string leftpad(u64 num, usize len) {
         auto tmp = std::to_string(num);
         while(tmp.length()<len) {
             tmp = " "+tmp;
@@ -65,7 +69,7 @@ public:
             std::exit(1);
         }
     }
-    u32 geterr() const {return cnt;}
+    auto geterr() const { return cnt; }
 };
 
 }
diff --git a/src/nasal_lexer.cpp b/src/nasal_lexer.cpp
index 628ab53..8e9da33 100644
--- a/src/nasal_lexer.cpp
+++ b/src/nasal_lexer.cpp
@@ -96,7 +96,7 @@ void lexer::open(const std::string& file) {
 }
 
 tok lexer::get_type(const std::string& str) {
-    return typetbl.count(str)? typetbl.at(str):tok::null;
+    return token_mapper.count(str)? token_mapper.at(str):tok::null;
 }
 
 std::string lexer::utf8_gen() {
@@ -138,8 +138,8 @@ std::string lexer::utf8_gen() {
 }
 
 token lexer::id_gen() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     std::string str = "";
     while(ptr<res.size() && (is_id(res[ptr]) || is_dec(res[ptr]))) {
         if (res[ptr]<0) { // utf-8
@@ -157,8 +157,8 @@ token lexer::id_gen() {
 }
 
 token lexer::num_gen() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     // generate hex number
     if (ptr+1<res.size() && res[ptr]=='0' && res[ptr+1]=='x') {
         std::string str = "0x";
@@ -239,8 +239,8 @@ token lexer::num_gen() {
 }
 
 token lexer::str_gen() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     std::string str = "";
     const char begin = res[ptr];
     ++column;
@@ -298,8 +298,8 @@ token lexer::str_gen() {
 }
 
 token lexer::single_opr() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     std::string str(1, res[ptr]);
     ++column;
     tok type = get_type(str);
@@ -314,8 +314,8 @@ token lexer::single_opr() {
 }
 
 token lexer::dots() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     std::string str = ".";
     if (ptr+2<res.size() && res[ptr+1]=='.' && res[ptr+2]=='.') {
         str += "..";
@@ -326,8 +326,8 @@ token lexer::dots() {
 }
 
 token lexer::calc_opr() {
-    u32 begin_line = line;
-    u32 begin_column = column;
+    u64 begin_line = line;
+    u64 begin_column = column;
     // get calculation operator
     std::string str(1, res[ptr++]);
     if (ptr<res.size() && res[ptr]=='=') {
diff --git a/src/nasal_lexer.h b/src/nasal_lexer.h
index bd0a778..a37ebe4 100644
--- a/src/nasal_lexer.h
+++ b/src/nasal_lexer.h
@@ -88,8 +88,8 @@ struct token {
 
 class lexer {
 private:
-    u32 line;
-    u32 column;
+    u64 line;
+    u64 column;
     usize ptr;
     std::string filename;
     std::string res;
@@ -98,7 +98,7 @@ private:
     u64 invalid_char;
     std::vector<token> toks;
 
-    const std::unordered_map<std::string, tok> typetbl {
+    const std::unordered_map<std::string, tok> token_mapper = {
         {"use"     ,tok::use     },
         {"true"    ,tok::tktrue  },
         {"false"   ,tok::tkfalse },
diff --git a/src/nasal_opcode.h b/src/nasal_opcode.h
index 687a32c..9a3b835 100644
--- a/src/nasal_opcode.h
+++ b/src/nasal_opcode.h
@@ -101,7 +101,7 @@ struct opcode {
     u8  op;   // opcode
     u16 fidx; // source code file index
     u32 num;  // immediate num
-    u32 line; // location line of source code
+    u64 line; // location line of source code
     opcode() = default;
     opcode(const opcode&) = default;
     opcode& operator=(const opcode&) = default;
diff --git a/src/nasal_parse.cpp b/src/nasal_parse.cpp
index 06e40a1..dc3b1a2 100644
--- a/src/nasal_parse.cpp
+++ b/src/nasal_parse.cpp
@@ -105,7 +105,7 @@ bool parse::check_comma(const tok* panic_set) {
 }
 
 bool parse::check_tuple() {
-    u32 check_ptr=ptr, curve=1, bracket=0, brace=0;
+    u64 check_ptr = ptr, curve = 1, bracket = 0, brace = 0;
     while(toks[++check_ptr].type!=tok::eof && curve) {
         switch(toks[check_ptr].type) {
             case tok::lcurve:   ++curve;   break;
@@ -157,7 +157,7 @@ bool parse::check_in_curve_multi_definition() {
 
 bool parse::check_special_call() {
     // special call means like this: function_name(a:1,b:2,c:3);
-    u32 check_ptr = ptr, curve = 1, bracket = 0, brace = 0;
+    u64 check_ptr = ptr, curve = 1, bracket = 0, brace = 0;
     while(toks[++check_ptr].type!=tok::eof && curve) {
         switch(toks[check_ptr].type) {
             case tok::lcurve:   ++curve;  break;
diff --git a/src/nasal_parse.h b/src/nasal_parse.h
index f662770..2d8ff27 100644
--- a/src/nasal_parse.h
+++ b/src/nasal_parse.h
@@ -15,9 +15,9 @@ class parse {
 #define prevspan (ptr!=0? toks[ptr-1].loc:toks[ptr].loc)
 
 private:
-    u32 ptr;
-    u32 in_func; // count function block
-    u32 in_loop; // count loop block
+    u64 ptr;
+    u64 in_func; // count function block
+    u64 in_loop; // count loop block
     const token* toks;
     code_block* root;
     error err;
diff --git a/src/nasal_vm.cpp b/src/nasal_vm.cpp
index 68f8031..496155f 100644
--- a/src/nasal_vm.cpp
+++ b/src/nasal_vm.cpp
@@ -451,7 +451,7 @@ void vm::run(
         &&mcallv, &&mcallh, &&ret
     };
     std::vector<const void*> code;
-    for(auto& i : gen.codes()) {
+    for(const auto& i : gen.codes()) {
         code.push_back(oprs[i.op]);
         imm.push_back(i.num);
     }
@@ -506,7 +506,7 @@ void vm::run(
         &vm::o_ret
     };
     std::vector<nafunc> code;
-    for(auto& i : gen.codes()) {
+    for(const auto& i : gen.codes()) {
         code.push_back(oprs[i.op]);
         imm.push_back(i.num);
     }
diff --git a/src/natives/nasal_builtin.cpp b/src/natives/nasal_builtin.cpp
index 04e695b..15af44a 100644
--- a/src/natives/nasal_builtin.cpp
+++ b/src/natives/nasal_builtin.cpp
@@ -339,6 +339,7 @@ var builtin_left(context* ctx, gc* ngc) {
     auto local = ctx->localr;
     var str = local[1];
     var len = local[2];
+
     if (!str.is_str()) {
         return nas_err("left", "\"string\" must be string");
     }
@@ -355,20 +356,23 @@ var builtin_right(context* ctx, gc* ngc) {
     auto local = ctx->localr;
     var str = local[1];
     var len = local[2];
+
     if (!str.is_str()) {
         return nas_err("right", "\"string\" must be string");
     }
     if (!len.is_num()) {
         return nas_err("right", "\"length\" must be number");
     }
+
     i32 length = static_cast<i32>(len.num());
-    i32 srclen = str.str().length();
+    i32 srclen = static_cast<i32>(str.str().length());
     if (length>srclen) {
         length = srclen;
     }
     if (length<0) {
         length = 0;
     }
+
     return ngc->newstr(str.str().substr(srclen-length, srclen));
 }
 
@@ -566,12 +570,12 @@ public:
     }
 
     f64 elapsed_milliseconds() {
-        auto duration = std::chrono::high_resolution_clock::now() - stamp;
+        const auto duration = std::chrono::high_resolution_clock::now() - stamp;
         return std::chrono::duration_cast<std::chrono::milliseconds>(duration).count();
     }
 
     f64 elapsed_microseconds() {
-        auto duration = std::chrono::high_resolution_clock::now() - stamp;
+        const auto duration = std::chrono::high_resolution_clock::now() - stamp;
         return std::chrono::duration_cast<std::chrono::microseconds>(duration).count();
     }
 };
diff --git a/src/natives/nasal_builtin.h b/src/natives/nasal_builtin.h
index 9ca7503..28674cd 100644
--- a/src/natives/nasal_builtin.h
+++ b/src/natives/nasal_builtin.h
@@ -66,10 +66,12 @@ var builtin_values(context*, gc*);
 var builtin_sleep(context*, gc*);
 var builtin_platform(context*, gc*);
 var builtin_arch(context*, gc*);
+
 // md5 related functions
 std::string tohex(u32);
 std::string md5(const std::string&);
 var builtin_md5(context*, gc*);
+
 var builtin_maketimestamp(context*, gc*);
 var builtin_time_stamp(context*, gc*);
 var builtin_elapsed_millisecond(context*, gc*);
diff --git a/tools/pack.py b/tools/pack.py
index 63aa477..3be7d00 100644
--- a/tools/pack.py
+++ b/tools/pack.py
@@ -4,8 +4,6 @@ import os
 import platform
 import shutil
 
-nasal_version = "11.2"
-
 build_directory = pathlib.Path("build")
 if not os.path.exists(build_directory):
     print("pack binaries failed: build directory not found")