#ifndef BOOST_MPL_AUX_AT_IMPL_HPP_INCLUDED

#define BOOST_MPL_AUX_AT_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_/at_impl.hpp,v $

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

// $Revision: 1.5 $

#include <boost/mpl/begin_end.hpp>

#include <boost/mpl/advance.hpp>

#include <boost/mpl/deref.hpp>

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

namespace boost { namespace mpl {

// default implementation; conrete sequences might override it by 

// specializing either the 'at_impl' or the primary 'at' template

template< typename Tag >

struct at_impl

{

    template< typename Sequence, typename N > struct apply

    {

        typedef typename advance<

              typename begin<Sequence>::type

            , N

            >::type iter_;

        typedef typename deref<iter_>::type type;

    };

};

BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, at_impl)

}}

#endif // BOOST_MPL_AUX_AT_IMPL_HPP_INCLUDED