diff --git a/scripts/moc.py b/scripts/moc.py
index eef73a1f..5ee3b35c 100644
--- a/scripts/moc.py
+++ b/scripts/moc.py
@@ -28,6 +28,8 @@ for n in [4,3,2,1]:
         c_args = ['VM*'] + [mapping[i] for i in p_args]
         c_ret = mapping[p_ret]
         name = f'__f_{p_ret}__{"_".join(p_args)}'
+        # if c_ret == 'const char*':
+        #     c_ret = 'char*'
         s = f'typedef {c_ret} (*{name})({", ".join(c_args)});'
         s += '\n'
 
diff --git a/src/builtins.h b/src/builtins.h
index b653ea25..dc18bc4b 100644
--- a/src/builtins.h
+++ b/src/builtins.h
@@ -270,42 +270,6 @@ class dict:
             a.append(k.__json__()+': '+v.__json__())
         return '{'+ ', '.join(a) + '}'
 
-import ffi
-
-def input():
-  return ffi.input()
-
-class FileIO:
-  def __init__(self, path, mode):
-    assert type(path) is str
-    assert type(mode) is str
-    assert mode in ['r', 'w', 'rt', 'wt']
-    self.path = path
-    self.mode = mode
-    self.fp = ffi.fopen(path, mode)
-
-  def read(self):
-    assert self.mode in ['r', 'rt']
-    return ffi.fread(self.fp)
-
-  def write(self, s):
-    assert self.mode in ['w', 'wt']
-    assert type(s) is str
-    ffi.fwrite(self.fp, s)
-
-  def close(self):
-    ffi.fclose(self.fp)
-
-  def __enter__(self):
-    pass
-
-  def __exit__(self):
-    self.close()
-
-def open(path, mode='r'):
-    return FileIO(path, mode)
-
-
 class set:
     def __init__(self, iterable=None):
         iterable = iterable or []
diff --git a/src/main.cpp b/src/main.cpp
index 6d92eed0..1a18ecb7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3,31 +3,28 @@
 
 #include "pocketpy.h"
 
-#define PK_DEBUG_TIME
-
 struct Timer{
     const char* title;
     Timer(const char* title) : title(title) {}
     void run(std::function<void()> f){
-#ifdef PK_DEBUG_TIME
         auto start = std::chrono::high_resolution_clock::now();
         f();
         auto end = std::chrono::high_resolution_clock::now();
         double elapsed = std::chrono::duration_cast<std::chrono::microseconds>(end - start).count() / 1000000.0;
         std::cout << title << ": " << elapsed << " s" << std::endl;
-#else
-        f();
-#endif
     }
 };
 
-
-
 #ifndef __NO_MAIN
 
 int main(int argc, char** argv){
+    VM* vm = pkpy_new_vm(true);
+    pkpy_vm_bind__f_str__(vm, "builtins", "input", [](VM* vm){
+        static std::string line;
+        std::getline(std::cin, line);
+        return line.c_str();
+    });
     if(argc == 1){
-        VM* vm = pkpy_new_vm(true);
         REPL repl(vm);
         int result = -1;
         while(true){
@@ -36,6 +33,7 @@ int main(int argc, char** argv){
             std::getline(std::cin, line);
             result = pkpy_repl_input(&repl, line.c_str());
         }
+        pkpy_delete(vm);
         return 0;
     }
     
@@ -49,13 +47,17 @@ int main(int argc, char** argv){
             return 1;
         }
         std::string src((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());
+        PyVarOrNull ret = nullptr;
 
-        VM* vm = pkpy_new_vm(true);
-        Timer("Running time").run([=]{
-            vm->exec(src.c_str(), filename, EXEC_MODE);
-        });
+        if(filename[0] != '_'){
+            Timer("Running time").run([&]{
+                ret = vm->exec(src.c_str(), filename, EXEC_MODE);
+            });
+        }else{
+            ret = vm->exec(src.c_str(), filename, EXEC_MODE);
+        }
         pkpy_delete(vm);
-        return 0;
+        return ret != nullptr ? 0 : 1;
     }
 
 __HELP:
diff --git a/src/pocketpy.h b/src/pocketpy.h
index a1885f75..94a5a65a 100644
--- a/src/pocketpy.h
+++ b/src/pocketpy.h
@@ -765,9 +765,6 @@ extern "C" {
         __add_module_math(vm);
         __add_module_re(vm);
         __add_module_dis(vm);
-        
-
-        vm->new_module("ffi");
 
         // add builtins | no exception handler | must succeed
         _Code code = vm->compile(__BUILTINS_CODE, "<builtins>", EXEC_MODE);