99 lines
2.9 KiB
C++
99 lines
2.9 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#if !defined(FUSION_BEGIN_04052005_1132)
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#define FUSION_BEGIN_04052005_1132
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#include <boost/fusion/support/config.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/mpl/empty_base.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/fusion/sequence/intrinsic_fwd.hpp>
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#include <boost/fusion/support/tag_of.hpp>
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#include <boost/fusion/support/is_sequence.hpp>
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#include <boost/fusion/support/is_segmented.hpp>
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#include <boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp>
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namespace boost { namespace fusion
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{
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// Special tags:
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struct sequence_facade_tag; // iterator facade tag
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struct boost_tuple_tag; // boost::tuples::tuple tag
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struct boost_array_tag; // boost::array tag
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struct mpl_sequence_tag; // mpl sequence tag
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struct std_pair_tag; // std::pair tag
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namespace extension
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{
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template <typename Tag>
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struct begin_impl
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{
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template <typename Sequence>
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struct apply
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: mpl::if_<
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traits::is_segmented<Sequence>
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, detail::segmented_begin<Sequence>
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, mpl::empty_base
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>::type
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{};
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};
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template <>
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struct begin_impl<sequence_facade_tag>
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{
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template <typename Sequence>
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struct apply : Sequence::template begin<Sequence> {};
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};
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template <>
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struct begin_impl<boost_tuple_tag>;
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template <>
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struct begin_impl<boost_array_tag>;
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template <>
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struct begin_impl<mpl_sequence_tag>;
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template <>
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struct begin_impl<std_pair_tag>;
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}
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namespace result_of
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{
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template <typename Sequence>
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struct begin
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: extension::begin_impl<typename detail::tag_of<Sequence>::type>::
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template apply<Sequence>
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{};
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}
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template <typename Sequence>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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inline typename
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lazy_enable_if<
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traits::is_sequence<Sequence>
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, result_of::begin<Sequence>
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>::type const
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begin(Sequence& seq)
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{
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return result_of::begin<Sequence>::call(seq);
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}
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template <typename Sequence>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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inline typename
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lazy_enable_if<
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traits::is_sequence<Sequence>
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, result_of::begin<Sequence const>
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>::type const
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begin(Sequence const& seq)
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{
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return result_of::begin<Sequence const>::call(seq);
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}
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}}
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#endif
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