diff --git a/src/main.cpp b/src/main.cpp
index 48141ad4..9a9eb107 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,8 +2,8 @@
 
 #include "pocketpy.h"
 
-//#define PK_DEBUG_TIME
-#define PK_DEBUG_THREADED_REPL
+#define PK_DEBUG_TIME
+//#define PK_DEBUG_THREADED
 
 struct Timer{
     const char* title;
@@ -65,7 +65,7 @@ void _tvm_dispatch(ThreadedVM* vm){
 
 int main(int argc, char** argv){
     if(argc == 1){
-#ifndef PK_DEBUG_THREADED_REPL
+#ifndef PK_DEBUG_THREADED
         VM* vm = pkpy_new_vm(true);
 #else
         ThreadedVM* vm = pkpy_new_tvm(true);
@@ -76,7 +76,7 @@ int main(int argc, char** argv){
             std::string line;
             std::getline(std::cin, line);
             int result = pkpy_repl_input(&repl, line.c_str());
-#ifdef PK_DEBUG_THREADED_REPL
+#ifdef PK_DEBUG_THREADED
             if(result == (int)EXEC_DONE){
                 _tvm_dispatch(vm);
                 pkpy_tvm_reset_state(vm);
@@ -103,19 +103,23 @@ int main(int argc, char** argv){
             code = compile(vm, src.c_str(), filename);
         });
         if(code == nullptr) return 1;
-        //std::cout << code->toString() << std::endl;
 
-        // Timer("Running time").run([=]{
-        //     vm->exec(code);
-        // });
+        //std::cout << code->toString() << std::endl;
 
         // for(auto& kv : _strIntern)
         //     std::cout << kv.first << ", ";
-
+        
+#ifdef PK_DEBUG_THREADED
         Timer("Running time").run([=]{
             vm->execAsync(code);
             _tvm_dispatch(vm);
         });
+#else
+        Timer("Running time").run([=]{
+            vm->exec(code);
+        });
+#endif
+
         pkpy_delete(vm);
         return 0;
     }
diff --git a/src/shared_ptr.h b/src/shared_ptr.h
index a8165f2d..cebc22a5 100644
--- a/src/shared_ptr.h
+++ b/src/shared_ptr.h
@@ -2,33 +2,20 @@
 
 #include "__stl__.h"
 
-// sooo slow! do not use this
 namespace pkpy{
     template <typename T>
     class shared_ptr {
         int* count;
         T* ptr;
-        const std::function<void(T*)>* deleter = nullptr;
 
-    void _delete(){
+    inline void _delete(){
         delete count;
-        if(deleter != nullptr) deleter->operator()(ptr);
-        else delete ptr;
+        delete ptr;
     }
 
     public:
         shared_ptr() : count(nullptr), ptr(nullptr) {}
         shared_ptr(T* ptr) : count(new int(1)), ptr(ptr) {}
-        shared_ptr(T* ptr, const std::function<void(T*)>*) : count(new int(1)), ptr(ptr), deleter(deleter) {}
-        shared_ptr(const shared_ptr& other) : count(other.count), ptr(other.ptr) {
-            if (count) {
-                ++(*count);
-            }
-        }
-        shared_ptr(shared_ptr&& other) : count(other.count), ptr(other.ptr) {
-            other.count = nullptr;
-            other.ptr = nullptr;
-        }
         ~shared_ptr() {
             if (count && --(*count) == 0) _delete();
         }
@@ -54,12 +41,11 @@ namespace pkpy{
                 if (count && --(*count) == 0) _delete();
                 count = other.count;
                 ptr = other.ptr;
-                if (count) {
-                    ++(*count);
-                }
+                if (count) ++(*count);  
             }
             return *this;
         }
+        
         shared_ptr& operator=(shared_ptr&& other) {
             if (this != &other) {
                 if (count && --(*count) == 0) _delete();
@@ -83,9 +69,6 @@ namespace pkpy{
         int use_count() const {
             return count ? *count : 0;
         }
-        explicit operator bool() const {
-            return ptr != nullptr;
-        }
     };
 
     template <typename T, typename... Args>
diff --git a/src/vm.h b/src/vm.h
index 7c9a7d78..fbf51ebb 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -1150,12 +1150,11 @@ public:
 
     PyVarOrNull exec(const _Code& code, PyVar _module = nullptr) override {
         if(_state == THREAD_READY) return VM::exec(code, _module);
-        UNREACHABLE();
-        // auto callstackBackup = std::move(callstack);
-        // callstack.clear();
-        // PyVarOrNull ret = VM::exec(code, _module);
-        // callstack = std::move(callstackBackup);
-        // return ret;
+        auto callstackBackup = std::move(callstack);
+        callstack.clear();
+        PyVarOrNull ret = VM::exec(code, _module);
+        callstack = std::move(callstackBackup);
+        return ret;
     }
 
     void resetState(){