set up so reusing scope when in a loop

src/runtime/objects/object.c

@@ -20,7 +20,7 @@ const char *built_in_field_names[BUILT_IN_FIELDS_COUNT] = {
     "__string__",  "__subtract__", "__multiply__", "__division__",
     "__new__",     "__init__",     "__boolean__",  "__get_attr__",
     "__binding__", "__function__", "address",      "__call__",
-    "__number__",  "log"};
+    "__number__",  "log", "length"};
 
 uint64_t built_in_field_hashes[BUILT_IN_FIELDS_COUNT];
 

src/runtime/objects/object.h

@@ -30,6 +30,7 @@ typedef enum {
   __call__,
   __number__,
   field_log,
+  field_length,
   BUILT_IN_FIELDS_COUNT
 } built_in_fields;
 

src/runtime/objects/string/string.c

@@ -17,7 +17,7 @@ ArgonObject *new_string_object(char *data, size_t length, uint64_t prehash,
                                uint64_t hash) {
   ArgonObject *object = new_object();
   add_builtin_field(object, __class__, ARGON_STRING_TYPE);
-  add_builtin_field(object, length,
+  add_builtin_field(object, field_length,
                     new_number_object_from_num_and_den(length, 1));
   object->type = TYPE_STRING;
   object->value.as_str.data = ar_alloc_atomic(length);