diff --git a/src/common/sstream.c b/src/common/sstream.c
index 46c68855..25cdc65a 100644
--- a/src/common/sstream.c
+++ b/src/common/sstream.c
@@ -12,7 +12,7 @@
 
 void c11_sbuf__ctor(c11_sbuf* self) {
     c11_vector__ctor(&self->data, sizeof(char));
-    c11_vector__reserve(&self->data, 100 + sizeof(c11_string));
+    c11_vector__reserve(&self->data, sizeof(c11_string) + 100);
     self->data.count = sizeof(c11_string);
 }
 
@@ -23,14 +23,16 @@ void c11_sbuf__write_char(c11_sbuf* self, char c) { c11_vector__push(char, &self
 void c11_sbuf__write_int(c11_sbuf* self, int i) {
     // len('-2147483648') == 11
     c11_vector__reserve(&self->data, self->data.count + 11 + 1);
-    int n = snprintf(self->data.data, 11 + 1, "%d", i);
+    char* p = self->data.data + self->data.count;
+    int n = snprintf(p, 11 + 1, "%d", i);
     self->data.count += n;
 }
 
 void c11_sbuf__write_i64(c11_sbuf* self, int64_t val) {
     // len('-9223372036854775808') == 20
     c11_vector__reserve(&self->data, self->data.count + 20 + 1);
-    int n = snprintf(self->data.data, 20 + 1, "%lld", (long long)val);
+    char* p = self->data.data + self->data.count;
+    int n = snprintf(p, 20 + 1, "%lld", (long long)val);
     self->data.count += n;
 }
 
@@ -134,7 +136,7 @@ void c11_sbuf__write_ptr(c11_sbuf* self, void* p) {
 c11_string* c11_sbuf__submit(c11_sbuf* self) {
     c11_vector__push(char, &self->data, '\0');
     c11_array arr = c11_vector__submit(&self->data);
-    c11_string* retval = (c11_string*)arr.data;
+    c11_string* retval = arr.data;
     retval->size = arr.count - sizeof(c11_string) - 1;
     return retval;
 }
diff --git a/src/interpreter/ceval.c b/src/interpreter/ceval.c
index 5629aaa7..1cf0b7d0 100644
--- a/src/interpreter/ceval.c
+++ b/src/interpreter/ceval.c
@@ -653,6 +653,7 @@ pk_FrameResult pk_VM__run_top_frame(pk_VM* self) {
     __ERROR:
         // 1. Exception can be handled inside the current frame
         // 2. Exception need to be propagated to the upper frame
+        printf("byte.op: %d, line: %d\n", byte.op, Frame__lineno(frame));
         assert(false);
         return RES_ERROR;
     }
diff --git a/src/public/vm.c b/src/public/vm.c
index abc40e6a..a4ed705c 100644
--- a/src/public/vm.c
+++ b/src/public/vm.c
@@ -49,9 +49,9 @@ static void disassemble(CodeObject* co) {
         Bytecode byte = c11__getitem(Bytecode, &co->codes, i);
         BytecodeEx ex = c11__getitem(BytecodeEx, &co->codes_ex, i);
 
-        char line[8];
+        char line[8] = "";
         if(ex.lineno == prev_line) {
-            line[0] = '\0';
+            // do nothing
         } else {
             snprintf(line, sizeof(line), "%d", ex.lineno);
             if(prev_line != -1) c11_sbuf__write_char(&ss, '\n');
@@ -66,7 +66,7 @@ static void disassemble(CodeObject* co) {
             }
         }
 
-        char buf[64];
+        char buf[32];
         snprintf(buf, sizeof(buf), "%-8s%-3s%-3d", line, pointer, i);
         c11_sbuf__write_cstr(&ss, buf);
 
@@ -132,6 +132,13 @@ static void disassemble(CodeObject* co) {
                     c11_sbuf__write_char(&ss, ')');
                     break;
                 }
+                case OP_BINARY_OP: {
+                    py_Name name = byte.arg & 0xFF;
+                    c11_sbuf__write_cstr(&ss, " (");
+                    c11_sbuf__write_cstr(&ss, py_name2str(name));
+                    c11_sbuf__write_char(&ss, ')');
+                    break;
+                }
             }
         } while(0);
 
diff --git a/src2/main.c b/src2/main.c
index 45676900..1dc6281e 100644
--- a/src2/main.c
+++ b/src2/main.c
@@ -25,6 +25,7 @@ int main(int argc, char** argv) {
     SetConsoleOutputCP(CP_UTF8);
 #endif
 
+#if 0
     py_initialize();
     const char* source = "1 < 2";
 
@@ -47,20 +48,18 @@ int main(int argc, char** argv) {
 
     py_finalize();
     return 0;
+#endif
 
-    //     if(argc != 2) goto __HELP;
-    //     char* source = read_file(argv[1]);
-    //     py_initialize();
+    if(argc != 2) goto __HELP;
+    char* source = read_file(argv[1]);
+    py_initialize();
 
-    //     if(py_exec(source)){
-    //         py_Error* err = py_getlasterror();
-    //         py_Error__print(err);
-    //     }
+    if(!py_exec(source)) py_printexc();
 
-    //     py_finalize();
-    //     free(source);
+    py_finalize();
+    free(source);
 
-    // __HELP:
-    //     printf("Usage: pocketpy [filename]\n");
-    //     return 0;
+__HELP:
+    printf("Usage: pocketpy [filename]\n");
+    return 0;
 }