change to 0-based

include/pocketpy/pocketpy.h

@@ -115,13 +115,13 @@ PK_EXPORT bool py_eval(const char* source, py_Ref module) PY_RAISE PY_RETURN;
 /// Example:
 /// `py_newstr(py_r0(), "abc");`
 /// `py_newint(py_r1(), 123);`
-/// `py_smartexec("print(_1, _2)", NULL, py_r0(), py_r1());`
+/// `py_smartexec("print(_0, _1)", NULL, py_r0(), py_r1());`
 /// `// "abc 123" will be printed`.
 PK_EXPORT bool py_smartexec(const char* source, py_Ref module, ...) PY_RAISE PY_RETURN;
 /// Evaluate a source string with smart interpretation.
 /// Example:
 /// `py_newstr(py_r0(), "abc");`
-/// `py_smarteval("len(_1)", NULL, py_r0());`
+/// `py_smarteval("len(_)", NULL, py_r0());`
 /// `int res = py_toint(py_retval());`
 /// `// res will be 3`.
 PK_EXPORT bool py_smarteval(const char* source, py_Ref module, ...) PY_RAISE PY_RETURN;

src/public/modules.c

@@ -536,14 +536,14 @@ static bool
     // [globals, locals, code]
     CodeObject* co = py_touserdata(py_peek(-1));
     py_StackRef locals = py_peek(-2);
-    int max_index = 0;
+    int max_index = -1;
     c11__foreach(Bytecode, &co->codes, bc) {
         if(bc->op == OP_LOAD_NAME) {
             c11_sv name = py_name2sv(bc->arg);
             if(name.data[0] != '_') continue;
             int index;
             if(name.size == 1) {
-                index = 1;
+                index = 0;
             } else if(name.size == 2 && isdigit(name.data[1])) {
                 index = name.data[1] - '0';
             } else {
@@ -553,17 +553,17 @@ static bool
         }
     }
 
-    if(max_index == 0) { return ValueError("no placeholder found in the source"); }
+    if(max_index == -1) return ValueError("no placeholder found in the source");
 
-    for(int i = 1; i <= max_index; i++) {
+    for(int i = 0; i <= max_index; i++) {
         py_Ref val = va_arg(args, py_Ref);
         char buf[3];
         buf[0] = '_';
         buf[1] = '0' + i;
         buf[2] = '\0';
         py_dict_setitem_by_str(locals, buf, val);
-        if(i == 1) {
-            // _ => _1
+        if(i == 0) {
+            // _ => _0
             py_dict_setitem_by_str(locals, "_", val);
         }
     }