boost/fusion/container/list/detail/empty_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2007 Tobias Schwinger
   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(BOOST_FUSION_SEQUENCE_EMPTY_IMPL_HPP_INCLUDED)
   8 #define BOOST_FUSION_SEQUENCE_EMPTY_IMPL_HPP_INCLUDED
   9
  10 #include <boost/type_traits/is_convertible.hpp>
  11
  12 namespace boost { namespace fusion
  13 {
  14     struct cons_tag;
  15
  16     struct nil;
  17
  18     template <typename Car, typename Cdr>
  19     struct cons;
  20
  21     namespace extension
  22     {
  23         template <typename Tag>
  24         struct empty_impl;
  25
  26         template <>
  27         struct empty_impl<cons_tag>
  28         {
  29             template <typename Sequence>
  30             struct apply
  31                 : boost::is_convertible<Sequence, nil>
  32             {};
  33         };
  34     }
  35 }}
  36
  37 #endif