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_FRONT_09162005_0343)
8 #define FUSION_FRONT_09162005_0343
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/fusion/sequence/intrinsic_fwd.hpp>
12 #include <boost/fusion/sequence/intrinsic/begin.hpp>
13 #include <boost/fusion/iterator/deref.hpp>
14 #include <boost/mpl/bool.hpp>
15 
16 namespace boost { namespace fusion
17 {
18     struct fusion_sequence_tag;
19 
20     namespace result_of
21     {
22         template <typename Sequence>
23         struct front
24             : result_of::deref<typename result_of::begin<Sequence>::type>
25         {};
26     }
27 
28     template <typename Sequence>
29     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
30     inline typename result_of::front<Sequence>::type
front(Sequence & seq)31     front(Sequence& seq)
32     {
33         return *fusion::begin(seq);
34     }
35 
36     template <typename Sequence>
37     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
38     inline typename result_of::front<Sequence const>::type
front(Sequence const & seq)39     front(Sequence const& seq)
40     {
41         return *fusion::begin(seq);
42     }
43 }}
44 
45 #endif
46