cppmp/include/cppmp/traits/lambda_traits.inl

#pragma once

#include <cppmp/core/checker.h>
#include <cppmp/core/conditionals.h>

#include "lambda_traits.h"

namespace cppmp
{

    namespace __impl
    {

        /* lambda_traits_impl */

        template<bool B_is_mutable, typename T_object, typename T_return, typename... T_args>
        struct lambda_traits_impl
        {
            using object_type       = T_object;
            using return_type       = T_return;
            using arguments_type    = std::tuple<T_args...>;

            using is_mutable        = bool_t<B_is_mutable>;
            using is_static         = is_same<object_type, void>;
            using argument_count    = size_t<sizeof...(T_args)>;

            static constexpr decltype(auto) is_mutable_v     = is_mutable::value;
            static constexpr decltype(auto) is_static_v      = is_static::value;
            static constexpr decltype(auto) argument_count_v = argument_count::value;

            template<std::size_t I>
            struct argument
                : public std::tuple_element<I, arguments_type>
                { };

            template<std::size_t I>
            using argument_t = typename argument<I>::type;
        };

    }

    /* lambda_traits */

    template<typename T_lambda>
    struct lambda_traits<
        T_lambda,
        enable_if_t<
            is_valid<decltype(&T_lambda::operator())>::value
        >>
        : public lambda_traits<decltype(&T_lambda::operator())>
        { };

    template<typename T_return, typename... T_args>
    struct lambda_traits<T_return (*)(T_args...), void>
        : public __impl::lambda_traits_impl<false, void, T_return, T_args...>
        { };

    template<typename T_object, typename T_return, typename... T_args>
    struct lambda_traits<T_return (T_object::*)(T_args...), void>
        : public __impl::lambda_traits_impl<true, T_object, T_return, T_args...>
        { };

    template<typename T_object, typename T_return, typename... T_args>
    struct lambda_traits<T_return (T_object::*)(T_args...) const, void>
        : public __impl::lambda_traits_impl<false, const T_object, T_return, T_args...>
        { };

}