3rdparty/boost/boost/fusion/container/list/detail/next_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3     Copyright (c) 2005 Eric Niebler
   4
   5     Distributed under the Boost Software License, Version 1.0. (See accompanying
   6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 ==============================================================================*/
   8 #if !defined(FUSION_NEXT_IMPL_07172005_0836)
   9 #define FUSION_NEXT_IMPL_07172005_0836
  10
  11 #include <boost/fusion/support/config.hpp>
  12 #include <boost/fusion/iterator/next.hpp>
  13 #include <boost/fusion/iterator/equal_to.hpp>
  14 #include <boost/mpl/eval_if.hpp>
  15 #include <boost/mpl/identity.hpp>
  16 #include <boost/type_traits/is_const.hpp>
  17 #include <boost/type_traits/add_const.hpp>
  18
  19 namespace boost { namespace fusion
  20 {
  21     struct cons_iterator_tag;
  22
  23     template <typename Cons>
  24     struct cons_iterator;
  25
  26     namespace extension
  27     {
  28         template <typename Tag>
  29         struct next_impl;
  30
  31         template <>
  32         struct next_impl<cons_iterator_tag>
  33         {
  34             template <typename Iterator>
  35             struct apply
  36             {
  37                 typedef typename Iterator::cons_type cons_type;
  38                 typedef typename cons_type::cdr_type cdr_type;
  39
  40                 typedef cons_iterator<
  41                     typename mpl::eval_if<
  42                         is_const<cons_type>
  43                       , add_const<cdr_type>
  44                       , mpl::identity<cdr_type>
  45                     >::type>
  46                 type;
  47
  48                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  49                 static type
  50                 call(Iterator const& i)
  51                 {
  52                     return type(i.cons.cdr);
  53                 }
  54             };
  55         };
  56     }
  57 }}
  58
  59 #endif
  60
  61