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

    Copyright (c) 2001-2006 Joel de Guzman



    Distributed under 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_FACADE_09252006_1011)

#define FUSION_ITERATOR_FACADE_09252006_1011



#include <boost/fusion/support/iterator_base.hpp>

#include <boost/fusion/iterator/detail/advance.hpp>

#include <boost/fusion/support/category_of.hpp>

#include <boost/type_traits/is_same.hpp>

#include <boost/mpl/assert.hpp>



namespace boost { namespace fusion

{

    struct iterator_facade_tag;



    template <typename Derived, typename Category>

    struct iterator_facade : iterator_base<Derived>

    {

        typedef iterator_facade_tag fusion_tag;

        typedef Derived derived_type;

        typedef Category category;



        // default implementation

        template <typename I1, typename I2>

        struct equal_to // default implementation

            : is_same<

                typename I1::derived_type

              , typename I2::derived_type

            >

        {};



        // default implementation

        template <typename Iterator, typename N>

        struct advance :

            mpl::if_c<

                (N::value > 0)

              , advance_detail::forward<Iterator, N::value>

              , advance_detail::backward<Iterator, N::value>

            >::type

        {

            BOOST_MPL_ASSERT_NOT((traits::is_random_access<Iterator>));

        };

    };

}}



#endif

