ceph/src/boost/boost/fusion/support/is_view.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_IS_VIEW_03202006_0015)
   8 #define FUSION_IS_VIEW_03202006_0015
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/mpl/bool.hpp>
  12 #include <boost/fusion/support/tag_of.hpp>
  13
  14 namespace boost { namespace fusion
  15 {
  16     // Special tags:
  17     struct non_fusion_tag;
  18     struct sequence_facade_tag;
  19     struct boost_tuple_tag; // boost::tuples::tuple tag
  20     struct boost_array_tag; // boost::array tag
  21     struct mpl_sequence_tag; // mpl sequence tag
  22     struct std_pair_tag; // std::pair tag
  23
  24     namespace extension
  25     {
  26         template<typename Tag>
  27         struct is_view_impl
  28         {
  29             template <typename T>
  30             struct apply
  31             {
  32                 typedef typename T::is_view type;
  33             };
  34         };
  35
  36         template <>
  37         struct is_view_impl<non_fusion_tag>
  38         {
  39             template <typename T>
  40             struct apply : mpl::false_ {};
  41         };
  42
  43         template <>
  44         struct is_view_impl<sequence_facade_tag>
  45         {
  46             template <typename Sequence>
  47             struct apply : Sequence::is_view {};
  48         };
  49
  50         template <>
  51         struct is_view_impl<boost_tuple_tag>;
  52
  53         template <>
  54         struct is_view_impl<boost_array_tag>;
  55
  56         template <>
  57         struct is_view_impl<mpl_sequence_tag>;
  58
  59         template <>
  60         struct is_view_impl<std_pair_tag>;
  61     }
  62
  63     namespace traits
  64     {
  65         template <typename T>
  66         struct is_view :
  67             mpl::bool_<
  68                 (bool)extension::is_view_impl<typename fusion::detail::tag_of<T>::type>::
  69                     template apply<T>::type::value
  70             >
  71         {};
  72     }
  73 }}
  74
  75 #endif