diff --git a/stl/padding.nas b/stl/padding.nas
new file mode 100644
index 0000000..47fc76a
--- /dev/null
+++ b/stl/padding.nas
@@ -0,0 +1,16 @@
+# padding.nas
+# ValKmjolnir 2022/9/4
+
+var leftpad=func(str,len,char=" "){
+    var strlen=size(str);
+    for(var i=strlen;i<len;i+=1)
+        str=char~str;
+    return str;
+}
+
+var rightpad=func(str,len,char=" "){
+    var strlen=size(str);
+    for(var i=strlen;i<len;i+=1)
+        str~=char;
+    return str;
+}
\ No newline at end of file
diff --git a/stl/result.nas b/stl/result.nas
index c07dfd2..6631b88 100644
--- a/stl/result.nas
+++ b/stl/result.nas
@@ -1,29 +1,23 @@
 # result.nas
 # ValKmjolnir 2021
 
-var ResultTrait={
-    Ok:func(val){
-        me.ok=val;
-        me.flag=0;
-        return me;
-    },
-    Err:func(info){
-        me.err=info;
-        me.flag=1;
-        return me;
-    },
-    unwrap:func(){
-        if(me.flag)
-            die(me.err);
-        return me.ok;
-    }
-};
-
 var Result=func(){
+    var (ok,err,flag)=(nil,"",1);
     return{
-        ok:nil,
-        err:"",
-        flag:1,
-        parents:[ResultTrait]
+        Ok:func(val){
+            ok=val;
+            flag=0;
+            return me;
+        },
+        Err:func(info){
+            err=info;
+            flag=1;
+            return me;
+        },
+        unwrap:func(){
+            if(flag)
+                die(err);
+            return ok;
+        }
     };
 };
\ No newline at end of file
diff --git a/test/calc.nas b/test/calc.nas
index bd36c6d..55a7df4 100644
--- a/test/calc.nas
+++ b/test/calc.nas
@@ -1,89 +1,100 @@
+import.stl.padding;
+
 var source=[
-    "main.cpp         ",
-    "nasal_ast.h      ",
-    "nasal_builtin.h  ",
-    "nasal_codegen.h  ",
-    "nasal_dbg.h      ",
-    "nasal_err.h      ",
-    "nasal_gc.h       ",
-    "nasal_import.h   ",
-    "nasal_lexer.h    ",
-    "nasal_opt.h      ",
-    "nasal_parse.h    ",
-    "nasal_vm.h       ",
-    "nasal.h          "
+    "main.cpp",
+    "nasal_ast.h",
+    "nasal_builtin.h",
+    "nasal_codegen.h",
+    "nasal_dbg.h",
+    "nasal_err.h",
+    "nasal_gc.h",
+    "nasal_import.h",
+    "nasal_lexer.h",
+    "nasal_opt.h",
+    "nasal_parse.h",
+    "nasal_vm.h",
+    "nasal.h"
 ];
 
 var lib=[
-    "fg_env.nas       ",
-    "file.nas         ",
-    "lib.nas          ",
-    "list.nas         ",
-    "log.nas          ",
-    "module.nas       ",
-    "process_bar.nas  ",
-    "queue.nas        ",
-    "result.nas       ",
-    "sort.nas         ",
-    "stack.nas        "
+    "fg_env.nas",
+    "file.nas",
+    "lib.nas",
+    "list.nas",
+    "log.nas",
+    "module.nas",
+    "padding.nas",
+    "process_bar.nas",
+    "queue.nas",
+    "result.nas",
+    "sort.nas",
+    "stack.nas"
 ];
 
 var testfile=[
-    "ascii-art.nas    ",
-    "auto_crash.nas   ",
-    "bf.nas           ",
-    "bfcolored.nas    ",
-    "bfconvertor.nas  ",
-    "bfs.nas          ",
-    "bigloop.nas      ",
-    "bp.nas           ",
-    "calc.nas         ",
-    "choice.nas       ",
-    "class.nas        ",
-    "coroutine.nas    ",
-    "diff.nas         ",
-    "exception.nas    ",
-    "fib.nas          ",
-    "filesystem.nas   ",
-    "hexdump.nas      ",
-    "httptest.nas     ",
-    "json.nas         ",
-    "leetcode1319.nas ",
-    "lexer.nas        ",
-    "life.nas         ",
-    "loop.nas         ",
-    "mandel.nas       ",
-    "mandelbrot.nas   ",
-    "md5.nas          ",
-    "md5compare.nas   ",
-    "module_test.nas  ",
-    "nasal_test.nas   ",
-    "occupation.nas   ",
-    "pi.nas           ",
-    "ppmgen.nas       ",
-    "prime.nas        ",
-    "qrcode.nas       ",
-    "quick_sort.nas   ",
-    "scalar.nas       ",
-    "snake.nas        ",
-    "tetris.nas       ",
-    "trait.nas        ",
+    "ascii-art.nas",
+    "auto_crash.nas",
+    "bf.nas",
+    "bfcolored.nas",
+    "bfconvertor.nas",
+    "bfs.nas",
+    "bigloop.nas",
+    "bp.nas",
+    "calc.nas",
+    "choice.nas",
+    "class.nas",
+    "coroutine.nas",
+    "diff.nas",
+    "exception.nas",
+    "fib.nas",
+    "filesystem.nas",
+    "hexdump.nas",
+    "httptest.nas",
+    "json.nas",
+    "leetcode1319.nas",
+    "lexer.nas",
+    "life.nas",
+    "loop.nas",
+    "mandel.nas",
+    "mandelbrot.nas",
+    "md5.nas",
+    "md5compare.nas",
+    "module_test.nas",
+    "nasal_test.nas",
+    "occupation.nas",
+    "pi.nas",
+    "ppmgen.nas",
+    "prime.nas",
+    "qrcode.nas",
+    "quick_sort.nas",
+    "scalar.nas",
+    "snake.nas",
+    "tetris.nas",
+    "trait.nas",
     "turingmachine.nas",
-    "utf8chk.nas      ",
-    "watchdog.nas     ",
-    "wavecollapse.nas ",
-    "ycombinator.nas  "
+    "utf8chk.nas",
+    "watchdog.nas",
+    "wavecollapse.nas",
+    "ycombinator.nas"
 ];
 
 var module=[
-    "fib.cpp          ",
-    "keyboard.cpp     ",
-    "nasocket.cpp     ",
-    "libfib.nas       ",
-    "libkey.nas       ",
-    "libsock.nas      "
+    "fib.cpp",
+    "keyboard.cpp",
+    "nasocket.cpp",
+    "libfib.nas",
+    "libkey.nas",
+    "libsock.nas"
 ];
 
+var longest=func(vec...){
+    var len=0;
+    foreach(var v;vec)
+        foreach(var f;v)
+            len=size(f)>len?size(f):len;
+    return len;
+}
+
 var getname=func(s){
     var (len,ch)=(size(s),' '[0]);
     for(var i=0;i<len and s[i]!=ch;i+=1);
@@ -100,10 +111,12 @@ var count=func(s,c){
 var calc=func(codetype,files,path=""){
     println(codetype);
     var (bytes,line,semi,line_cnt,semi_cnt)=(0,0,0,0,0);
+    var padding_length=longest(source,lib,testfile,module);
     forindex(var i;files){
         var s=io.fin(getname(path~files[i]));
         (line_cnt,semi_cnt)=(count(s,'\n'),count(s,';'));
-        println(files[i],'| ',line_cnt,'\tline | ',semi_cnt,' \tsemi');
+        println(rightpad(files[i],padding_length),
+            '| ',line_cnt,'\tline | ',semi_cnt,' \tsemi');
         bytes+=size(s);
         line+=line_cnt;
         semi+=semi_cnt;
@@ -113,5 +126,8 @@ var calc=func(codetype,files,path=""){
     return int(bytes/1024);
 }
 
-var all=calc("source code:",source)+calc("lib:",lib,"stl/")+calc("test file:",testfile,"test/")+calc("module:",module,"module/");
+var all=calc("source code:",source)
+    +calc("lib:",lib,"stl/")
+    +calc("test file:",testfile,"test/")
+    +calc("module:",module,"module/");
 println('\ntotal:           | ',all,'\tkb');
\ No newline at end of file
diff --git a/test/md5compare.nas b/test/md5compare.nas
index 64102cb..b339a31 100644
--- a/test/md5compare.nas
+++ b/test/md5compare.nas
@@ -35,6 +35,7 @@ var filechecksum=func(){
         "./stl/fg_env.nas",        "./stl/file.nas",
         "./stl/lib.nas",           "./stl/list.nas",
         "./stl/log.nas",           "./stl/module.nas",
+        "./stl/padding.nas",
         "./stl/process_bar.nas",   "./stl/queue.nas",
         "./stl/result.nas",        "./stl/sort.nas",
         "./stl/stack.nas",         "./test/ascii-art.nas",
diff --git a/test/occupation.nas b/test/occupation.nas
index 59c6131..6e609f9 100644
--- a/test/occupation.nas
+++ b/test/occupation.nas
@@ -50,10 +50,10 @@ func(){
         var bar=process_bar.bar("block","point","line",25);
         if(key!=nil and chr(key)=="q")
             break;
-        println("\e[1;1H Memory total(GB)    : \e[36m",mem.MemTotal/1024/1024,"\e[0m");
-        println("\e[2;1H Memory free(GB)     : \e[36m",mem.MemFree/1024/1024,"\e[0m");
-        println("\e[3;1H Memory occupation(%): ",mem_occ>60?"\e[91m":"\e[32m",bar.bar(mem_occ/100)~" ",mem_occ,"\e[0m         ");
-        println("\e[4;1H CPU occupation(%)   : ",cpu_occ>90?"\e[91m":"\e[32m",bar.bar(cpu_occ/100)~" ",cpu_occ,"\e[0m         ");
+        println("\e[1;1H\e[1m Memory total(GB)    : \e[0m\e[36m",mem.MemTotal/1024/1024,"\e[0m");
+        println("\e[2;1H\e[1m Memory free(GB)     : \e[0m\e[36m",mem.MemFree/1024/1024,"\e[0m");
+        println("\e[3;1H\e[1m Memory occupation(%): \e[0m",mem_occ>60?"\e[91m":"\e[32m",bar.bar(mem_occ/100)~" ",mem_occ,"\e[0m         ");
+        println("\e[4;1H\e[1m CPU occupation(%)   : \e[0m",cpu_occ>90?"\e[91m":"\e[32m",bar.bar(cpu_occ/100)~" ",cpu_occ,"\e[0m         ");
         println("\e[5;1H Press 'q' to quit.");
     }
 }();
\ No newline at end of file