arg.hpp

// Copyright (C) 2022-2023 by Camden Mannett.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "arg_router/multi_arg_base.hpp"
#include "arg_router/policy/description.hpp"
#include "arg_router/policy/long_name.hpp"
#include "arg_router/policy/short_name.hpp"
#include "arg_router/utility/string_to_policy.hpp"
 
namespace arg_router
{
template <typename T, typename... Policies>
class arg_t :
    public multi_arg_base_t<T,
                            1,
                            policy::min_max_count_t<traits::integral_constant<std::size_t{1}>,
                                                    traits::integral_constant<std::size_t{1}>>,
                            std::decay_t<Policies>...>
{
    using parent_type =
        multi_arg_base_t<T,
                         1,
                         policy::min_max_count_t<traits::integral_constant<std::size_t{1}>,
                                                 traits::integral_constant<std::size_t{1}>>,
                         std::decay_t<Policies>...>;
 
    static_assert(!traits::has_none_name_method_v<arg_t>, "Arg must not have a none name policy");
    static_assert(!traits::has_display_name_method_v<arg_t>,
                  "Arg must not have a display name policy");
 
public:
    using typename parent_type::policies_type;
 
    using value_type = typename parent_type::value_type;
 
    template <bool Flatten>
    using help_data_type = typename parent_type::template default_leaf_help_data_type<Flatten>;
 
    constexpr explicit arg_t(Policies... policies) noexcept :
        parent_type{policy::min_max_count_t<traits::integral_constant<std::size_t{1}>,
                                            traits::integral_constant<std::size_t{1}>>{},
                    std::move(policies)...}
    {
    }
 
    template <typename Validator, bool HasTarget, typename... Parents>
    [[nodiscard]] std::optional<parsing::parse_target> pre_parse(
        parsing::pre_parse_data<Validator, HasTarget> pre_parse_data,
        const Parents&... parents) const
 
    {
        return parent_type::pre_parse(pre_parse_data, *this, parents...);
    }
 
    template <typename... Parents>
    value_type parse(parsing::parse_target&& target, const Parents&... parents) const
    {
        return parent_type::parse(target, *this, parents...);
    }
};
 
template <typename T, typename... Policies>
[[nodiscard]] constexpr auto arg(Policies... policies) noexcept
{
    return std::apply(
        [](auto... converted_policies) {
            return arg_t<T, std::decay_t<decltype(converted_policies)>...>{
                std::move(converted_policies)...};
        },
        utility::string_to_policy::convert<
            utility::string_to_policy::first_string_mapper<policy::long_name_t>,
            utility::string_to_policy::second_string_mapper<policy::description_t>,
            utility::string_to_policy::single_char_mapper<policy::short_name_t>>(
            std::move(policies)...));
}
}  // namespace arg_router