diff --git a/CMakeLists.txt b/CMakeLists.txt
index cbecc8d..00f7218 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,7 +17,7 @@ set(CMAKE_BUILD_TYPE "Release")
 # build nasal used object
 set(NASAL_OBJECT_SOURCE_FILE
     ${CMAKE_SOURCE_DIR}/src/cli/cli.cpp
-    ${CMAKE_SOURCE_DIR}/src/natives/nasal_builtin.cpp
+    ${CMAKE_SOURCE_DIR}/src/natives/builtin.cpp
     ${CMAKE_SOURCE_DIR}/src/natives/coroutine.cpp
     ${CMAKE_SOURCE_DIR}/src/natives/fg_props.cpp
     ${CMAKE_SOURCE_DIR}/src/natives/bits_lib.cpp
diff --git a/README.md b/README.md
index e8b5158..df1701f 100644
--- a/README.md
+++ b/README.md
@@ -26,11 +26,9 @@
 
 __Contact us if having great ideas to share!__
 
-* __E-mail__:
+* __lhk101lhk101@qq.com__ (ValKmjolnir)
 
-  * __lhk101lhk101@qq.com__ (ValKmjolnir)
-
-  * __sidi.liang@gmail.com__ (Sidi)
+* __sidi.liang@gmail.com__ (Sidi)
 
 ## __Introduction__
 
diff --git a/doc/README_zh.md b/doc/README_zh.md
index 0cdd1da..c5b0831 100644
--- a/doc/README_zh.md
+++ b/doc/README_zh.md
@@ -26,11 +26,9 @@
 
 __如果有好的意见或建议，欢迎联系我们!__
 
-* __E-mail__:
+* __lhk101lhk101@qq.com__ (ValKmjolnir)
 
-  * __lhk101lhk101@qq.com__ (ValKmjolnir)
-
-  * __1467329765@qq.com__(Sidi762)
+* __sidi.liang@gmail.com__ (Sidi)
 
 ## __简介__
 
diff --git a/makefile b/makefile
index a496739..12b42a1 100644
--- a/makefile
+++ b/makefile
@@ -13,7 +13,7 @@ NASAL_HEADER = \
 	src/ast_dumper.h\
 	src/ast_visitor.h\
 	src/nasal_ast.h\
-	src/natives/nasal_builtin.h\
+	src/natives/builtin.h\
 	src/nasal_codegen.h\
 	src/nasal_dbg.h\
 	src/nasal_err.h\
@@ -54,7 +54,7 @@ NASAL_OBJECT = \
 	build/nasal_codegen.o\
 	build/nasal_misc.o\
 	build/nasal_gc.o\
-	build/nasal_builtin.o\
+	build/builtin.o\
 	build/fg_props.o\
 	build/io_lib.o\
 	build/math_lib.o\
@@ -127,12 +127,12 @@ build/nasal_ast.o: \
 	src/nasal_ast.h src/nasal_ast.cpp | build
 	$(CXX) $(CXXFLAGS) src/nasal_ast.cpp -o build/nasal_ast.o
 
-build/nasal_builtin.o: \
+build/builtin.o: \
 	src/nasal.h\
 	src/nasal_type.h\
 	src/nasal_gc.h\
-	src/natives/nasal_builtin.h src/natives/nasal_builtin.cpp | build
-	$(CXX) $(CXXFLAGS) src/natives/nasal_builtin.cpp -o build/nasal_builtin.o
+	src/natives/builtin.h src/natives/builtin.cpp | build
+	$(CXX) $(CXXFLAGS) src/natives/builtin.cpp -o build/builtin.o
 
 build/coroutine.o: \
 	src/nasal.h\
@@ -203,7 +203,7 @@ build/nasal_codegen.o: $(NASAL_HEADER) src/nasal_codegen.h src/nasal_codegen.cpp
 
 build/nasal_opcode.o: \
 	src/nasal.h\
-	src/natives/nasal_builtin.h\
+	src/natives/builtin.h\
 	src/nasal_opcode.h src/nasal_opcode.cpp | build
 	$(CXX) $(CXXFLAGS) src/nasal_opcode.cpp -o build/nasal_opcode.o
 
diff --git a/src/nasal_codegen.h b/src/nasal_codegen.h
index 2b4ba53..8501426 100644
--- a/src/nasal_codegen.h
+++ b/src/nasal_codegen.h
@@ -8,7 +8,7 @@
 #include "nasal_parse.h"
 #include "nasal_import.h"
 
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 #include "natives/coroutine.h"
 #include "natives/bits_lib.h"
 #include "natives/math_lib.h"
diff --git a/src/nasal_opcode.h b/src/nasal_opcode.h
index fd2502c..55e81c8 100644
--- a/src/nasal_opcode.h
+++ b/src/nasal_opcode.h
@@ -1,7 +1,7 @@
 #pragma once
 
 #include "nasal.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 #include <iostream>
 
diff --git a/src/nasal_type.cpp b/src/nasal_type.cpp
index 91feb10..cdb6b38 100644
--- a/src/nasal_type.cpp
+++ b/src/nasal_type.cpp
@@ -384,7 +384,7 @@ nas_map& var::map() {
 }
 
 var nas_err(const std::string& error_function_name, const std::string& info) {
-    std::cerr << "\n[vm] " << error_function_name << ": " << info << "\n";
+    std::cerr << "[vm] " << error_function_name << ": " << info << "\n";
     return var::none();
 }
 
diff --git a/src/nasal_vm.cpp b/src/nasal_vm.cpp
index f5d205a..abf9454 100644
--- a/src/nasal_vm.cpp
+++ b/src/nasal_vm.cpp
@@ -75,8 +75,8 @@ void vm::value_info(var& val) {
         case vm_type::vm_nil:  std::clog << "| nil  |"; break;
         case vm_type::vm_num:  std::clog << "| num  | " << val.num(); break;
         case vm_type::vm_str:  std::clog << "| str  | <0x" << std::hex << p
-                                         << "> " << rawstr(val.str(), 16)
-                                         << std::dec; break;
+                                         << "> \"" << rawstr(val.str(), 16)
+                                         << "\"" << std::dec; break;
         case vm_type::vm_func: std::clog << "| func | <0x" << std::hex << p
                                          << std::dec << "> " << val.func();
                                          break;
@@ -391,7 +391,7 @@ std::string vm::type_name_string(const var& value) const {
 }
 
 void vm::die(const std::string& str) {
-    std::cerr << "\n[vm] error: " << str << "\n";
+    std::cerr << "[vm] error: " << str << "\n";
     function_call_trace();
     trace_back();
     stack_info();
diff --git a/src/natives/bits_lib.h b/src/natives/bits_lib.h
index 49f160d..a1673bb 100644
--- a/src/natives/bits_lib.h
+++ b/src/natives/bits_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/nasal_builtin.cpp b/src/natives/builtin.cpp
similarity index 89%
rename from src/natives/nasal_builtin.cpp
rename to src/natives/builtin.cpp
index d9beaba..39da951 100644
--- a/src/natives/nasal_builtin.cpp
+++ b/src/natives/builtin.cpp
@@ -1,4 +1,4 @@
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 #include <chrono>
 
 #ifdef _WIN32
@@ -45,7 +45,7 @@ var builtin_append(context* ctx, gc* ngc) {
     var vec = local[1];
     var elem = local[2];
     if (!vec.is_vec()) {
-        return nas_err("append", "\"vec\" must be vector");
+        return nas_err("native::append", "\"vec\" must be vector");
     }
     auto& v = vec.vec().elems;
     for(auto& i : elem.vec().elems) {
@@ -59,7 +59,7 @@ var builtin_setsize(context* ctx, gc* ngc) {
     var vec = local[1];
     var size = local[2];
     if (!vec.is_vec()) {
-        return nas_err("setsize", "\"vec\" must be vector");
+        return nas_err("native::setsize", "\"vec\" must be vector");
     }
     if (!size.is_num() || size.num()<0) {
         return nil;
@@ -93,10 +93,10 @@ var builtin_split(context* ctx, gc* ngc) {
     var delimeter = local[1];
     var str = local[2];
     if (!delimeter.is_str()) {
-        return nas_err("split", "\"separator\" must be string");
+        return nas_err("native::split", "\"separator\" must be string");
     }
     if (!str.is_str()) {
-        return nas_err("split", "\"str\" must be string");
+        return nas_err("native::split", "\"str\" must be string");
     }
     const auto& deli = delimeter.str();
     const auto& s = str.str();
@@ -131,7 +131,7 @@ var builtin_split(context* ctx, gc* ngc) {
 var builtin_rand(context* ctx, gc* ngc) {
     auto val = ctx->localr[1];
     if (!val.is_num() && !val.is_nil()) {
-        return nas_err("rand", "\"seed\" must be nil or number");
+        return nas_err("native::rand", "\"seed\" must be nil or number");
     }
     if (val.is_num()) {
         srand(static_cast<u32>(val.num()));
@@ -191,7 +191,7 @@ var builtin_num(context* ctx, gc* ngc) {
 var builtin_pop(context* ctx, gc* ngc) {
     auto val = ctx->localr[1];
     if (!val.is_vec()) {
-        return nas_err("pop", "\"vec\" must be vector");
+        return nas_err("native::pop", "\"vec\" must be vector");
     }
     auto& vec = val.vec().elems;
     if (vec.size()) {
@@ -224,7 +224,7 @@ var builtin_size(context* ctx, gc* ngc) {
 var builtin_time(context* ctx, gc* ngc) {
     auto val = ctx->localr[1];
     if (!val.is_num()) {
-        return nas_err("time", "\"begin\" must be number");
+        return nas_err("native::time", "\"begin\" must be number");
     }
     auto begin = static_cast<time_t>(val.num());
     return var::num(static_cast<f64>(time(&begin)));
@@ -245,7 +245,7 @@ var builtin_delete(context* ctx, gc* ngc) {
     var hash = local[1];
     var key = local[2];
     if (!hash.is_hash()) {
-        return nas_err("delete", "\"hash\" must be hash");
+        return nas_err("native::delete", "\"hash\" must be hash");
     }
     if (!key.is_str()) {
         return nil;
@@ -259,7 +259,7 @@ var builtin_delete(context* ctx, gc* ngc) {
 var builtin_keys(context* ctx, gc* ngc) {
     auto hash = ctx->localr[1];
     if (!hash.is_hash() && !hash.is_map()) {
-        return nas_err("keys", "\"hash\" must be hash");
+        return nas_err("native::keys", "\"hash\" must be hash");
     }
     // avoid being sweeped
     auto res = ngc->temp = ngc->alloc(vm_type::vm_vec);
@@ -278,7 +278,7 @@ var builtin_keys(context* ctx, gc* ngc) {
 }
 
 var builtin_die(context* ctx, gc* ngc) {
-    return nas_err("error", ctx->localr[1].to_str());
+    return nas_err("native::error", ctx->localr[1].to_str());
 }
 
 var builtin_find(context* ctx, gc* ngc) {
@@ -315,18 +315,18 @@ var builtin_substr(context* ctx, gc* ngc) {
     var beg = local[2];
     var len = local[3];
     if (!str.is_str()) {
-        return nas_err("substr", "\"str\" must be string");
+        return nas_err("native::substr", "\"str\" must be string");
     }
     if (!beg.is_num() || beg.num()<0) {
-        return nas_err("substr", "\"begin\" should be number >= 0");
+        return nas_err("native::substr", "\"begin\" should be number >= 0");
     }
     if (!len.is_num() || len.num()<0) {
-        return nas_err("substr", "\"length\" should be number >= 0");
+        return nas_err("native::substr", "\"length\" should be number >= 0");
     }
     auto begin = static_cast<usize>(beg.num());
     auto length = static_cast<usize>(len.num());
     if (begin>=str.str().length()) {
-        return nas_err("susbtr", "begin index out of range: "+std::to_string(begin));
+        return nas_err("native::susbtr", "begin index out of range: "+std::to_string(begin));
     }
     return ngc->newstr(str.str().substr(begin, length));
 }
@@ -346,10 +346,10 @@ var builtin_left(context* ctx, gc* ngc) {
     var len = local[2];
 
     if (!str.is_str()) {
-        return nas_err("left", "\"string\" must be string");
+        return nas_err("native::left", "\"string\" must be string");
     }
     if (!len.is_num()) {
-        return nas_err("left", "\"length\" must be number");
+        return nas_err("native::left", "\"length\" must be number");
     }
     if (len.num()<0) {
         return ngc->newstr("");
@@ -363,10 +363,10 @@ var builtin_right(context* ctx, gc* ngc) {
     var len = local[2];
 
     if (!str.is_str()) {
-        return nas_err("right", "\"string\" must be string");
+        return nas_err("native::right", "\"string\" must be string");
     }
     if (!len.is_num()) {
-        return nas_err("right", "\"length\" must be number");
+        return nas_err("native::right", "\"length\" must be number");
     }
 
     i32 length = static_cast<i32>(len.num());
@@ -386,7 +386,7 @@ var builtin_cmp(context* ctx, gc* ngc) {
     var a = local[1];
     var b = local[2];
     if (!a.is_str() || !b.is_str()) {
-        return nas_err("cmp", "\"a\" and \"b\" must be string");
+        return nas_err("native::cmp", "\"a\" and \"b\" must be string");
     }
     return var::num(static_cast<f64>(strcmp(
         a.str().c_str(),
@@ -429,7 +429,7 @@ var builtin_char(context* ctx, gc* ngc) {
 var builtin_values(context* ctx, gc* ngc) {
     auto hash = ctx->localr[1];
     if (!hash.is_hash() && !hash.is_map()) {
-        return nas_err("values", "\"hash\" must be hash or namespace");
+        return nas_err("native::values", "\"hash\" must be hash or namespace");
     }
     auto vec = ngc->alloc(vm_type::vm_vec);
     auto& v = vec.vec().elems;
@@ -564,7 +564,7 @@ std::string md5(const std::string& src) {
 var builtin_md5(context* ctx, gc* ngc) {
     auto str = ctx->localr[1];
     if (!str.is_str()) {
-        return nas_err("md5", "\"str\" must be string");
+        return nas_err("native::md5", "\"str\" must be string");
     }
     return ngc->newstr(md5(str.str()));
 }
@@ -704,7 +704,7 @@ var builtin_logtime(context* ctx, gc* ngc) {
 var builtin_ghosttype(context* ctx, gc* ngc) {
     auto arg = ctx->localr[1];
     if (!arg.is_ghost()) {
-        return nas_err("ghosttype", "this is not a ghost object.");
+        return nas_err("native::ghosttype", "this is not a ghost object.");
     }
 
     const auto& name = arg.ghost().get_ghost_name();
diff --git a/src/natives/nasal_builtin.h b/src/natives/builtin.h
similarity index 100%
rename from src/natives/nasal_builtin.h
rename to src/natives/builtin.h
diff --git a/src/natives/coroutine.h b/src/natives/coroutine.h
index 7760e34..d0327d6 100644
--- a/src/natives/coroutine.h
+++ b/src/natives/coroutine.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/dylib_lib.h b/src/natives/dylib_lib.h
index 0998cba..3b49dea 100644
--- a/src/natives/dylib_lib.h
+++ b/src/natives/dylib_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 #ifdef _WIN32
 #include <windows.h>
diff --git a/src/natives/fg_props.h b/src/natives/fg_props.h
index 07bfdcf..a692169 100644
--- a/src/natives/fg_props.h
+++ b/src/natives/fg_props.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/io_lib.h b/src/natives/io_lib.h
index 6b3f6ea..3f2937f 100644
--- a/src/natives/io_lib.h
+++ b/src/natives/io_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 #ifndef _MSC_VER
 #include <unistd.h>
diff --git a/src/natives/json_lib.h b/src/natives/json_lib.h
index ad4fc86..830a121 100644
--- a/src/natives/json_lib.h
+++ b/src/natives/json_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/math_lib.h b/src/natives/math_lib.h
index 92dcd65..c6df825 100644
--- a/src/natives/math_lib.h
+++ b/src/natives/math_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/regex_lib.h b/src/natives/regex_lib.h
index ba0ceff..5e471f5 100644
--- a/src/natives/regex_lib.h
+++ b/src/natives/regex_lib.h
@@ -4,7 +4,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 namespace nasal {
 
diff --git a/src/natives/unix_lib.h b/src/natives/unix_lib.h
index 40d7d49..93a70aa 100644
--- a/src/natives/unix_lib.h
+++ b/src/natives/unix_lib.h
@@ -2,7 +2,7 @@
 
 #include "nasal.h"
 #include "nasal_gc.h"
-#include "natives/nasal_builtin.h"
+#include "natives/builtin.h"
 
 #ifndef _MSC_VER
 #include <unistd.h>
diff --git a/test/ascii-art.nas b/test/ascii-art.nas
index ce654a6..574c912 100644
--- a/test/ascii-art.nas
+++ b/test/ascii-art.nas
@@ -3,6 +3,23 @@ use std.process_bar;
 use std.unix;
 use std.runtime;
 
+var table_character_set = [
+    "─", "━", "│", "┃", "╌", "╍", "╎", "╏", "┄", "┅",
+    "┆", "┇", "┈", "┉", "┊", "┋", "┌", "┍", "┎", "┏",
+    "┐", "┑", "┒", "┓", "└", "┕", "┖", "┗", "┘", "┙",
+    "┚", "┛", "├", "┝", "┞", "┟", "┠", "┡", "┢", "┣",
+    "┤", "┥", "┦", "┧", "┨", "┩", "┪", "┫", "┬", "┭",
+    "┮", "┯", "┰", "┱", "┲", "┳", "┴", "┵", "┶", "┷",
+    "┸", "┹", "┺", "┻", "┼", "┽", "┾", "┿", "╀", "╁",
+    "╂", "╃", "╄", "╅", "╆", "╇", "╈", "╉", "╊", "╋",
+    "╪", "╫", "╬", "═", "║", "╒", "╓", "╔", "╕", "╖",
+    "╗", "╘", "╙", "╚", "╛", "╜", "╝", "╞", "╟", "╠",
+    "╡", "╢", "╣", "╤", "╥", "╦", "╧", "╨", "╬", "╩",
+    "┷", "┳", "⊥", "﹃", "﹄", "╮", "╭", "╯", "╰", "╳"
+];
+
+var selection_box = ["○", "◉", "☐", "▣"];
+
 var char_ttf=[
     ["    ","    ","    ","    ","    ","    "],
     [" █████╗ ","██╔══██╗","███████║","██╔══██║","██║  ██║","╚═╝  ╚═╝"],
diff --git a/test/wavecity.nas b/test/wavecity.nas
index 4484796..89d085b 100644
--- a/test/wavecity.nas
+++ b/test/wavecity.nas
@@ -2,23 +2,6 @@ use std.runtime;
 
 runtime.windows.set_utf8_output();
 
-var table_character_set = [
-    "─", "━", "│", "┃", "╌", "╍", "╎", "╏", "┄", "┅",
-    "┆", "┇", "┈", "┉", "┊", "┋", "┌", "┍", "┎", "┏",
-    "┐", "┑", "┒", "┓", "└", "┕", "┖", "┗", "┘", "┙",
-    "┚", "┛", "├", "┝", "┞", "┟", "┠", "┡", "┢", "┣",
-    "┤", "┥", "┦", "┧", "┨", "┩", "┪", "┫", "┬", "┭",
-    "┮", "┯", "┰", "┱", "┲", "┳", "┴", "┵", "┶", "┷",
-    "┸", "┹", "┺", "┻", "┼", "┽", "┾", "┿", "╀", "╁",
-    "╂", "╃", "╄", "╅", "╆", "╇", "╈", "╉", "╊", "╋",
-    "╪", "╫", "╬", "═", "║", "╒", "╓", "╔", "╕", "╖",
-    "╗", "╘", "╙", "╚", "╛", "╜", "╝", "╞", "╟", "╠",
-    "╡", "╢", "╣", "╤", "╥", "╦", "╧", "╨", "╩", "╔",
-    "╗", "╝", "╚", "╬", "═", "╓", "╩", "┠", "┨", "┯",
-    "┷", "┏", "┓", "┗", "┛", "┳", "⊥", "﹃", "﹄",
-    "╮", "╭", "╯", "╰", "╳"
-];
-
 var road_enum = {
     null: 0,
     narrow: 1,