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

    Copyright (c) 2001-2007 Joel de Guzman

    Copyright (c) 2005-2007 Dan Marsden



    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(BOOST_FUSION_AT_KEY_IMPL_20070508_2248)

#define BOOST_FUSION_AT_KEY_IMPL_20070508_2248



#include <boost/fusion/support/detail/access.hpp>



namespace boost { namespace fusion

{

    struct struct_tag;



    namespace extension

    {

        template<typename T>

        struct at_key_impl;



        template <typename Struct, typename Key>

        struct struct_assoc_member;



        template <>

        struct at_key_impl<struct_tag>

        {

            template <typename Sequence, typename Key>

            struct apply

            {

                typedef typename

                extension::struct_assoc_member<Sequence, Key>

                element;



                typedef typename

                    mpl::eval_if<

                        is_const<Sequence>

                      , detail::cref_result<element>

                      , detail::ref_result<element>

                    >::type

                type;



                static type

                call(Sequence& seq)

                {

                    return extension::

                        struct_assoc_member<Sequence, Key>::call(seq);

                }

            };

        };

    }

}}



#endif

