libcruft-util/cmdopt2/arg.hpp

/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Copyright 2022, Danny Robson <danny@nerdcruft.net>
 */

#pragma once

#include <cruft/util/debug/assert.hpp>
#include <cruft/util/parse/value.hpp>
#include <cruft/util/cast.hpp>

#include <optional>
#include <string>
#include <functional>


namespace cruft::cmdopt2 {
    struct argument {
        std::string name;
        std::optional<std::string> description;
        bool required = false;

        using acceptor1_t = std::function<void(std::string_view)>;
        std::optional<acceptor1_t> acceptor1;
    };


    template <typename BaseT>
    struct ops : argument {
        template <typename ValueT>
        BaseT bind (ValueT&&) = delete;

        template <typename ValueT>
        BaseT
        bind (ValueT &ref)
        {
            CHECK (!acceptor1);
            if constexpr (std::is_same_v<ValueT, std::string> or std::is_same_v<ValueT, char const*>) {
                acceptor1 = [&ref] (std::string_view str) { ref = str; };
            } else {
                acceptor1 = [&ref] (std::string_view str) { ref = parse::from_string<ValueT> (str); };
            }
            return get ();
        }

        template <typename ValueT>
        BaseT
        bind (std::optional<ValueT> &ref)
        {
            CHECK (!acceptor1);

            if constexpr (std::is_same_v<ValueT, std::string>) {
                acceptor1 = [&ref] (std::string_view str) { ref = str; };
            } else {
                acceptor1 = [&ref] (std::string_view str) { ref = parse::from_string<ValueT> (str); };
            }

            return get ();
        }

        BaseT
        get (void) const
        {
            return reinterpret_cast<BaseT const&> (*this);
        }
    };


    struct positional : public ops<positional> {
        static positional create (char const *name);
        static positional create (std::string_view name);
        static positional create (std::string const &name);
        static positional create (std::string &&name);

        int count = 1;
    };

    struct keyword : public ops<keyword> {
        using acceptor0_t = std::function<void(void)>;
        std::optional<acceptor0_t> acceptor0;

        static keyword create (char const *name);
        static keyword create (std::string_view name);
        static keyword create (std::string const &name);
        static keyword create (std::string &&name);

        keyword flag (void) const;
        keyword flag (std::string_view long_) const;
        keyword flag (char short_) const;

        keyword count   (int  &) const;
        keyword present (bool &) const;

        std::optional<char> short_;
        std::optional<std::string> long_;
    };
}