int main(string[] args) {
    var digits = PhpefRuntimeEmbed.phpfunc_ctype_digit(PhpefRuntimeCore.Zval.from_string("12345"));
    if (digits.kind != PhpefRuntimeCore.ValueKind.BOOL || !digits.as_bool()) {
        stderr.printf("unexpected ctype_digit(12345) result: %s\n", digits.to_php_string());
        return 1;
    }

    var not_digits = PhpefRuntimeEmbed.phpfunc_ctype_digit(PhpefRuntimeCore.Zval.from_string("12a45"));
    if (not_digits.kind != PhpefRuntimeCore.ValueKind.BOOL || not_digits.as_bool()) {
        stderr.printf("unexpected ctype_digit(12a45) result: %s\n", not_digits.to_php_string());
        return 1;
    }

    return 0;
}
