#ifndef BOOST_MPL_INSERT_IMPL_HPP_INCLUDED

#define BOOST_MPL_INSERT_IMPL_HPP_INCLUDED

// Copyright Aleksey Gurtovoy 2000-2004

//

// 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)

//

// See http://www.boost.org/libs/mpl for documentation.

// $Source: /cvsroot/boost/boost/boost/mpl/aux_/insert_impl.hpp,v $

// $Date: 2004/09/02 15:40:43 $

// $Revision: 1.4 $

#include <boost/mpl/reverse_fold.hpp>

#include <boost/mpl/iterator_range.hpp>

#include <boost/mpl/clear.hpp>

#include <boost/mpl/push_front.hpp>

#include <boost/mpl/aux_/na_spec.hpp>

#include <boost/mpl/aux_/traits_lambda_spec.hpp>

#include <boost/type_traits/is_same.hpp>

namespace boost { namespace mpl {

// default implementation; conrete sequences might override it by 

// specializing either the 'insert_impl' or the primary 'insert' template

template< typename Tag >

struct insert_impl

{

    template<

          typename Sequence

        , typename Pos

        , typename T

        >

    struct apply

    {

        typedef iterator_range<

              typename begin<Sequence>::type

            , Pos

            > first_half_;

        typedef iterator_range<

              Pos

            , typename end<Sequence>::type

            > second_half_;

        typedef typename reverse_fold<

              second_half_

            , typename clear<Sequence>::type

            , push_front<_,_>

            >::type half_sequence_;

        typedef typename reverse_fold<

              first_half_

            , typename push_front<half_sequence_,T>::type

            , push_front<_,_>

            >::type type;

    };

};

BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(3,insert_impl)

}}

#endif // BOOST_MPL_INSERT_IMPL_HPP_INCLUDED