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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 http://www.boost.org/LICENSE_1_0.txt)
- ==============================================================================*/
- #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::eval_if<
- mpl::bool_<N::value == 0>
- , mpl::identity<typename Sequence::car_type>
- , apply<typename Sequence::cdr_type, mpl::int_<N::value-1> >
- >::type
- type;
- };
- };
- }
- }}
- #endif
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