if (arg == NULL) goto EXPAND_FAILED;
yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
if (*s++ != '}') goto EXPAND_FAILED_CURLY;
if (arg == NULL) goto EXPAND_FAILED;
yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
if (*s++ != '}') goto EXPAND_FAILED_CURLY;