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_BACK_09162005_0350)
8#define FUSION_BACK_09162005_0350
9
10#include <boost/fusion/support/config.hpp>
11#include <boost/fusion/sequence/intrinsic_fwd.hpp>
12#include <boost/fusion/sequence/intrinsic/end.hpp>
13#include <boost/fusion/iterator/prior.hpp>
14#include <boost/fusion/iterator/deref.hpp>
15#include <boost/mpl/bool.hpp>
16
17namespace boost { namespace fusion
18{
19 struct fusion_sequence_tag;
20
21 namespace result_of
22 {
23 template <typename Sequence>
24 struct back
25 : result_of::deref<typename result_of::prior<typename result_of::end<Sequence>::type>::type>
26 {};
27 }
28
29 template <typename Sequence>
30 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
31 inline typename result_of::back<Sequence>::type
32 back(Sequence& seq)
33 {
34 return *fusion::prior(fusion::end(seq));
35 }
36
37 template <typename Sequence>
38 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
39 inline typename result_of::back<Sequence const>::type
40 back(Sequence const& seq)
41 {
42 return *fusion::prior(fusion::end(seq));
43 }
44}}
45
46#endif
47