Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2011 Joel de Guzman
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying 
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #if !defined(FUSION_BEGIN_04052005_1132)
Chris@16: #define FUSION_BEGIN_04052005_1132
Chris@16: 
Chris@101: #include <boost/fusion/support/config.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@101: #include <boost/mpl/empty_base.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/fusion/sequence/intrinsic_fwd.hpp>
Chris@16: #include <boost/fusion/support/tag_of.hpp>
Chris@16: #include <boost/fusion/support/is_sequence.hpp>
Chris@16: #include <boost/fusion/support/is_segmented.hpp>
Chris@16: #include <boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp>
Chris@16: 
Chris@16: namespace boost { namespace fusion
Chris@16: {
Chris@16:     // Special tags:
Chris@16:     struct sequence_facade_tag; // iterator facade tag
Chris@16:     struct boost_tuple_tag; // boost::tuples::tuple tag
Chris@16:     struct boost_array_tag; // boost::array tag
Chris@16:     struct mpl_sequence_tag; // mpl sequence tag
Chris@16:     struct std_pair_tag; // std::pair tag
Chris@16: 
Chris@16:     namespace extension
Chris@16:     {
Chris@16:         template <typename Tag>
Chris@16:         struct begin_impl
Chris@16:         {
Chris@16:             template <typename Sequence>
Chris@16:             struct apply
Chris@16:               : mpl::if_<
Chris@16:                     traits::is_segmented<Sequence>
Chris@16:                   , detail::segmented_begin<Sequence>
Chris@101:                   , mpl::empty_base
Chris@16:                 >::type
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<sequence_facade_tag>
Chris@16:         {
Chris@16:             template <typename Sequence>
Chris@16:             struct apply : Sequence::template begin<Sequence> {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<boost_tuple_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<boost_array_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<mpl_sequence_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<std_pair_tag>;
Chris@16:     }
Chris@16: 
Chris@16:     namespace result_of
Chris@16:     {
Chris@16:         template <typename Sequence>
Chris@16:         struct begin
Chris@16:             : extension::begin_impl<typename detail::tag_of<Sequence>::type>::
Chris@16:                 template apply<Sequence>
Chris@16:         {};
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Sequence>
Chris@101:     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:     inline typename
Chris@16:         lazy_enable_if<
Chris@16:             traits::is_sequence<Sequence>
Chris@16:           , result_of::begin<Sequence>
Chris@16:         >::type const
Chris@16:     begin(Sequence& seq)
Chris@16:     {
Chris@16:         return result_of::begin<Sequence>::call(seq);
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Sequence>
Chris@101:     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:     inline typename
Chris@16:         lazy_enable_if<
Chris@16:             traits::is_sequence<Sequence>
Chris@16:           , result_of::begin<Sequence const>
Chris@16:         >::type const
Chris@16:     begin(Sequence const& seq)
Chris@16:     {
Chris@16:         return result_of::begin<Sequence const>::call(seq);
Chris@16:     }
Chris@16: }}
Chris@16: 
Chris@16: #endif