/*=============================================================================

    Copyright (c) 2003 Joel de Guzman



    Use, modification and distribution is subject to the Boost Software

    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at

    http://www.boost.org/LICENSE_1_0.txt)

==============================================================================*/

#if !defined(FUSION_ITERATOR_DETAIL_TUPLE_ITERATOR_EQUAL_TO_TRAITS_HPP)

#define FUSION_ITERATOR_DETAIL_TUPLE_ITERATOR_EQUAL_TO_TRAITS_HPP



#include <boost/spirit/fusion/detail/config.hpp>

#include <boost/type_traits/is_same.hpp>

#include <boost/mpl/equal_to.hpp>

#include <boost/mpl/and.hpp>



namespace boost { namespace fusion

{

    struct tuple_iterator_tag;



    namespace detail

    {

        template <typename I1, typename I2>

        struct has_same_tags

            : is_same<FUSION_GET_TAG(I1), FUSION_GET_TAG(I2)> {};



        template <typename I1, typename I2>

        struct has_same_index

            : mpl::equal_to<FUSION_GET_INDEX(I1), FUSION_GET_INDEX(I2)>::type {};



        template <typename I>

        struct tuple_identity

        {

            typedef typename I::tuple tuple_type;

            typedef typename tuple_type::identity_type type;

        };



        template <typename I1, typename I2>

        struct has_same_tuple_identity

            : is_same<

                typename tuple_identity<I1>::type

              , typename tuple_identity<I2>::type

            >

        {};



        template <typename I1, typename I2>

        struct tuple_iterator_equal_to

            : mpl::and_<

                has_same_index<I1, I2>

              , has_same_tuple_identity<I1, I2>

            >

        {

            BOOST_STATIC_ASSERT((has_same_tags<I1, I2>::value));

        };

    }



    namespace meta

    {

        template <typename Tag>

        struct equal_to_impl;



        template <>

        struct equal_to_impl<tuple_iterator_tag>

        {

            template <typename I1, typename I2>

            struct apply : detail::tuple_iterator_equal_to<I1, I2> {};

        };

    }

}}



#endif



