Method param

src/common/clipp.h:4528–4531

        const arg_string& arg() const noexcept { return arg_; }

        const parameter* param() const noexcept {
            return match_ && match_->is_param()
                ? &(match_->as_param()) : nullptr;
        }

        std::size_t repeat() const noexcept { return repeat_; }