public String toString() {
            return "{ \"" + name + "\", "
                + (hasArg == NO_ARG ? "NO_ARG"
                    : hasArg == REQ_ARG ? "REQ_ARG"
                    : hasArg == OPT_ARG ? "OPT_ARG"
                    : ("" + hasArg))
                + ", '" + val + "' }";
        }