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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_AT_05042005_0722)
- #define FUSION_AT_05042005_0722
- #include <boost/fusion/support/config.hpp>
- #include <boost/mpl/int.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/mpl/or.hpp>
- #include <boost/mpl/less.hpp>
- #include <boost/mpl/empty_base.hpp>
- #include <boost/type_traits/is_const.hpp>
- #include <boost/fusion/sequence/intrinsic_fwd.hpp>
- #include <boost/fusion/support/tag_of.hpp>
- #include <boost/fusion/support/category_of.hpp>
- namespace boost { namespace fusion
- {
- // Special tags:
- struct sequence_facade_tag;
- struct boost_tuple_tag; // boost::tuples::tuple tag
- struct boost_array_tag; // boost::array tag
- struct mpl_sequence_tag; // mpl sequence tag
- struct std_pair_tag; // std::pair tag
- struct std_tuple_tag; // std::tuple tag
- namespace extension
- {
- template <typename Tag>
- struct at_impl
- {
- template <typename Sequence, typename N>
- struct apply;
- };
- template <>
- struct at_impl<sequence_facade_tag>
- {
- template <typename Sequence, typename N>
- struct apply : Sequence::template at<Sequence, N> {};
- };
- template <>
- struct at_impl<boost_tuple_tag>;
- template <>
- struct at_impl<boost_array_tag>;
- template <>
- struct at_impl<mpl_sequence_tag>;
- template <>
- struct at_impl<std_pair_tag>;
- template <>
- struct at_impl<std_tuple_tag>;
- }
- namespace detail
- {
- template <typename Sequence, typename N, typename Tag>
- struct at_impl
- : mpl::if_<
- mpl::or_<
- mpl::less<N, typename extension::size_impl<Tag>::template apply<Sequence>::type>
- , traits::is_unbounded<Sequence>
- >
- , typename extension::at_impl<Tag>::template apply<Sequence, N>
- , mpl::empty_base
- >::type
- {};
- }
- namespace result_of
- {
- template <typename Sequence, typename N>
- struct at
- : detail::at_impl<Sequence, N, typename detail::tag_of<Sequence>::type>
- {};
- template <typename Sequence, int N>
- struct at_c
- : at<Sequence, mpl::int_<N> >
- {};
- }
- template <typename N, typename Sequence>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- inline typename
- lazy_disable_if<
- is_const<Sequence>
- , result_of::at<Sequence, N>
- >::type
- at(Sequence& seq)
- {
- return result_of::at<Sequence, N>::call(seq);
- }
- template <typename N, typename Sequence>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- inline typename result_of::at<Sequence const, N>::type
- at(Sequence const& seq)
- {
- return result_of::at<Sequence const, N>::call(seq);
- }
- template <int N, typename Sequence>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- inline typename
- lazy_disable_if<
- is_const<Sequence>
- , result_of::at_c<Sequence, N>
- >::type
- at_c(Sequence& seq)
- {
- return result_of::at_c<Sequence, N>::call(seq);
- }
- template <int N, typename Sequence>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- inline typename result_of::at_c<Sequence const, N>::type
- at_c(Sequence const& seq)
- {
- return result_of::at_c<Sequence const, N>::call(seq);
- }
- }}
- #endif
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