ceph/src/boost/libs/fusion/include/boost/fusion/sequence/intrinsic/front.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(FUSION_FRONT_09162005_0343)
   8 #define FUSION_FRONT_09162005_0343
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/sequence/intrinsic_fwd.hpp>
  12 #include <boost/fusion/sequence/intrinsic/begin.hpp>
  13 #include <boost/fusion/iterator/deref.hpp>
  14 #include <boost/mpl/bool.hpp>
  15
  16 namespace boost { namespace fusion
  17 {
  18     struct fusion_sequence_tag;
  19
  20     namespace result_of
  21     {
  22         template <typename Sequence>
  23         struct front
  24             : result_of::deref<typename result_of::begin<Sequence>::type>
  25         {};
  26     }
  27
  28     template <typename Sequence>
  29     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  30     inline typename result_of::front<Sequence>::type
  31     front(Sequence& seq)
  32     {
  33         return *fusion::begin(seq);
  34     }
  35
  36     template <typename Sequence>
  37     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  38     inline typename result_of::front<Sequence const>::type
  39     front(Sequence const& seq)
  40     {
  41         return *fusion::begin(seq);
  42     }
  43 }}
  44
  45 #endif