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    Copyright (c) 2001-2011 Joel de Guzman

    Distributed under the Boost Software License, Version 1.0. (See accompanying 
    file LICENSE_1_0.txt or copy at
#if !defined(FUSION_VALUE_AT_IMPL_07172005_0952)
#define FUSION_VALUE_AT_IMPL_07172005_0952

#include <boost/fusion/support/config.hpp>
#include <boost/fusion/support/detail/access.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/bool.hpp>

namespace boost { namespace fusion
    struct cons_tag;

    namespace extension
        template <typename Tag>
        struct value_at_impl;

        template <>
        struct value_at_impl<cons_tag>
            template <typename Sequence, typename N>
            struct apply
                typedef typename
                        mpl::bool_<N::value == 0>
                      , mpl::identity<typename Sequence::car_type>
                      , apply<typename Sequence::cdr_type, mpl::int_<N::value-1> >