diff --git a/src/ccode.vala b/src/ccode.vala
index dad59f3..6a6d4a5 100755
--- a/src/ccode.vala
+++ b/src/ccode.vala
@@ -26,13 +26,6 @@ public extern int get_uid_by_user (string username);
 //DOC: chech root user
 public extern bool is_root ();
 
-// ### nostd.c
-// All private functions. please look util/interface.vala
-private extern void no_stdin ();
-private extern void no_stdout ();
-private extern void no_stderr ();
-private extern void reset_std ();
-
 //DOC: ### sandbox.c
 //DOC: `void sandbox (string type, string[] args):`
 //DOC: run command in sandboxed area
diff --git a/src/ccode/error.c b/src/ccode/error.c
index 4ba219f..136a52b 100755
--- a/src/ccode/error.c
+++ b/src/ccode/error.c
@@ -29,7 +29,6 @@ void error(int status){
     size_t len = 0;
     char** errs = array_get(error_arr, &len);
     if(len > 0 && !get_bool ("ignore-error")) {
-        printf("%ld\n", len);
         for(i=0;i<len;i++){
             if(errs[i] != NULL){
                 print_stderr(build_string("%s: %s", colorize(_ ("ERROR"), red), strdup(errs[i])));
diff --git a/src/ccode/logger.c b/src/ccode/logger.c
index e5257d5..7511418 100755
--- a/src/ccode/logger.c
+++ b/src/ccode/logger.c
@@ -2,27 +2,34 @@
 #include <string.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <stdbool.h>
+#include <time.h>
 
 /* functions from vala source */
-void print(char* msg);
-void print_stderr(char* msg);
-void error_add(char* msg);
 int get_bool(char* val);
 void colorize_init();
 
 /* string add function*/
 char* str_add(char* s1, char* s2);
 
+/* string builder */
+char* build_string(char* format, ...);
 
-/* headers of functions */
+
+extern char* colorize(char* message, int color);
+extern char* gettext(char* message);
+
+#define yellow 33
+#define green 32
+#define _(A) gettext(A)
+
+#include <error.h>
+#include <logger.h>
+
+/* define function headers */
 void cprint(char* msg);
 void cprint_stderr(char* msg);
 void cprint_dummy(char* msg);
-void warning_fn(char* msg);
-#ifdef DEBUG
-void debug_fn(char* msg);
-#endif
-void info_fn(char* msg);
 
 
 /* function pointer type definitions */
@@ -45,10 +52,46 @@ void print_fn(char* message, int new_line, int err){
     write(err+1, message, strlen(message));
 }
 
+void warning_fn (char* message) {
+    print_stderr (build_string("%s: %s",colorize (_ ("WARNING"), yellow), message));
+}
+
+void info_fn (char* message) {
+    print_stderr (build_string("%s: %s",colorize (_ ("INFO"), yellow), message));
+}
+
 void cprint(char* message){
     message = str_add(message, "\n");
     write(1, message, strlen(message));
 }
+
+
+void set_terminal_title (char* msg) {
+    #if NOCOLOR
+       return;
+    #else
+    if (!get_bool ("no-color")) {
+        print_fn (build_string("%s%s%s","\x1b]2;", msg, "\x07"), false, false);
+    }
+    #endif
+}
+
+
+#ifdef DEBUG
+static long last_debug_time = -1;
+void debug_fn(char *message) {
+    if (last_debug_time == -1) {
+        last_debug_time = time(NULL);
+    }
+
+    time_t current_time = time(NULL);
+    int elapsed_time = (int)(current_time - last_debug_time);
+
+    print_stderr (build_string( "[%s:%d]: %s\n", "DEBUG", elapsed_time, message));
+
+    last_debug_time = current_time;
+}
+#endif
 void cprint_stderr(char* message){
     message = str_add(message, "\n");
     write(2, message, strlen(message));
diff --git a/src/include/logger.h b/src/include/logger.h
new file mode 100755
index 0000000..a623004
--- /dev/null
+++ b/src/include/logger.h
@@ -0,0 +1,18 @@
+#ifndef LOGGER_H
+#define LOGGER_H
+
+void print(char* msg);
+void warning(char* msg);
+#if DEBUG
+void debug(char* msg);
+void debug_fn(char* message);
+#endif
+void info(char* msg);
+void print_stderr(char* msg);
+void warning_fn(char* message);
+void info_fn(char* message);
+void logger_init();
+void set_terminal_title(char* message);
+
+#endif /* LOGGER_H */
+
diff --git a/src/interpreter.vala b/src/interpreter.vala
index 3722afc..16e30cc 100755
--- a/src/interpreter.vala
+++ b/src/interpreter.vala
@@ -8,6 +8,10 @@ public void add_script(string data) {
     }
 }
 
+private extern void no_stdin();
+private extern void reset_std();
+
+
 public int ymp_run() {
     variable_integer[] labels = {};
     bool label_found = false;
@@ -78,10 +82,10 @@ public int ymp_run() {
         }
         lock_operation();
         if (get_bool("disable-stdin")) {
-            nostdin();
+            no_stdin();
         }
         int status = operation_main(proc[i].type, proc[i].args);
-        resetstd();
+        reset_std();
         unlock_operation();
         if (status != 0) {
             string type = proc[i].type;
diff --git a/src/util/interface.vala b/src/util/interface.vala
index 8db5d6b..c03bdfc 100755
--- a/src/util/interface.vala
+++ b/src/util/interface.vala
@@ -104,41 +104,3 @@ public void print_with_amogus (string data) {
     }
 
 }
-
-//DOC: `void nostdin ():`
-//DOC: close stdin. Ignore input. This function may broke application.
-public void nostdin () {
-    nostdin_enabled = true;
-    set_value_readonly ("ask", "false");
-    no_stdin ();
-}
-
-//DOC: `void nostdout ():`
-//DOC: close stdout
-public void nostdout () {
-    set_value_readonly ("no-stdout", "true");
-    no_stdout ();
-}
-
-//DOC: `void nostderr ():`
-//DOC: close stderr
-public void nostderr () {
-    set_value_readonly ("no-stderr", "true");
-    no_stderr ();
-}
-
-//DOC: `void resetstd ():`
-//DOC: restore stdout and stdin
-public void resetstd () {
-    set_value_readonly ("no-stdout", "false");
-    set_value_readonly ("no-stderr", "false");
-    reset_std ();
-}
-
-//DOC: `void nostd ():`
-//DOC: close stdin, stdout and stderr
-public void nostd () {
-    nostdin ();
-    nostdout ();
-    nostderr ();
-}
diff --git a/src/util/logger.vala b/src/util/logger.vala
deleted file mode 100755
index 7b0621c..0000000
--- a/src/util/logger.vala
+++ /dev/null
@@ -1,63 +0,0 @@
-
-//DOC: ## logging functions
-
-//DOC: `void print (string message):`
-//DOC: write standard messages to stdout
-//DOC: Example usage:
-//DOC: ```vala
-//DOC: print ("Hello world!");
-//DOC: ```
-public extern void print (string msg);
-//DOC: `void warning (string message):`
-//DOC: write warning message like this:
-//DOC: ```yaml
-//DOC: WARNING: message
-//DOC: ```
-public extern void warning (string msg);
-#if DEBUG
-//DOC: `void debug (string message):`
-//DOC: write debug messages. Its only print if debug mode enabled.
-public extern void debug (string msg);
-//DOC: `void info (string message):`
-//DOC: write additional info messages.
-#endif
-public extern void info (string msg);
-
-//DOC: `void print_stderr (string message):`
-//DOC: same with print but write to stderr
-public extern void print_stderr (string msg);
-
-public void warning_fn (string message) {
-    print_stderr ("%s: %s".printf (colorize (_ ("WARNING"), yellow), message));
-}
-
-#if DEBUG
-private long last_debug_time = -1;
-public void debug_fn (string message) {
-    if (last_debug_time == -1) {
-        last_debug_time = get_epoch();
-    }
-    print_stderr ("[%s:%d]: %s".printf (colorize (_ ("DEBUG"), blue), (int) (get_epoch () - last_debug_time) , message));
-    last_debug_time = get_epoch();
-}
-#endif
-
-public void info_fn (string message) {
-    print_stderr ("%s: %s".printf (colorize (_ ("INFO"), green), message));
-}
-
-public extern void logger_init ();
-
-
-//DOC: `void set_terminal_title (string msg):`
-//DOC: set terminal title
-public void set_terminal_title (string msg) {
-    #if NOCOLOR
-       return;
-    #else
-    if (!get_bool ("no-color")) {
-        print_fn ("\x1b]2;" + msg + "\x07", false, false);
-    }
-    #endif
-}
-
diff --git a/src/vapi/logger.vapi b/src/vapi/logger.vapi
new file mode 100755
index 0000000..f84adf8
--- /dev/null
+++ b/src/vapi/logger.vapi
@@ -0,0 +1,31 @@
+[CCode (cheader_filename = "logger.h")]
+public void print(string msg);
+
+[CCode (cheader_filename = "logger.h")]
+public void warning(string msg);
+
+#if DEBUG
+[CCode (cheader_filename = "logger.h")]
+public void debug(string msg);
+
+[CCode (cheader_filename = "logger.h")]
+public void debug_fn (string message);
+#endif
+
+[CCode (cheader_filename = "logger.h")]
+public void info(string msg);
+
+[CCode (cheader_filename = "logger.h")]
+public void print_stderr(string msg);
+
+[CCode (cheader_filename = "logger.h")]
+public void warning_fn (string message);
+
+[CCode (cheader_filename = "logger.h")]
+public void info_fn (string message);
+
+[CCode (cheader_filename = "logger.h")]
+public void logger_init ();
+
+[CCode (cheader_filename = "logger.h")]
+public void set_terminal_title (string message);