ceph/src/boost/boost/fusion/view/transform_view/detail/value_at_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3     Copyright (c) 2005-2006 Dan Marsden
   4     Copyright (c) 2018 Kohei Takahashi
   5
   6     Distributed under the Boost Software License, Version 1.0. (See accompanying
   7     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 ==============================================================================*/
   9 #if !defined(BOOST_FUSION_VALUE_AT_IMPL_20061101_0745)
  10 #define BOOST_FUSION_VALUE_AT_IMPL_20061101_0745
  11
  12 #include <boost/fusion/support/config.hpp>
  13 #include <boost/fusion/sequence/intrinsic/value_at.hpp>
  14 #include <boost/utility/result_of.hpp>
  15
  16 namespace boost { namespace fusion {
  17     struct transform_view_tag;
  18     struct transform_view2_tag;
  19
  20     namespace extension
  21     {
  22         template<typename Tag>
  23         struct value_at_impl;
  24
  25         template<>
  26         struct value_at_impl<transform_view_tag>
  27         {
  28             template<typename Seq, typename N>
  29             struct apply
  30             {
  31                 typedef typename Seq::transform_type F;
  32                 typedef typename result_of::value_at<typename Seq::sequence_type, N>::type value_type;
  33                 typedef typename boost::result_of<F(value_type)>::type type;
  34             };
  35         };
  36
  37         template<>
  38         struct value_at_impl<transform_view2_tag>
  39         {
  40             template<typename Seq, typename N>
  41             struct apply
  42             {
  43                 typedef typename Seq::transform_type F;
  44                 typedef typename result_of::value_at<typename Seq::sequence1_type, N>::type value1_type;
  45                 typedef typename result_of::value_at<typename Seq::sequence2_type, N>::type value2_type;
  46                 typedef typename boost::result_of<F(value1_type, value2_type)>::type type;
  47             };
  48         };
  49     }
  50 }}
  51
  52 #endif