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_BEGIN_IMPL_07172005_0824)
9 #define FUSION_BEGIN_IMPL_07172005_0824
10 
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/mpl/if.hpp>
13 #include <boost/type_traits/is_const.hpp>
14 
15 namespace boost { namespace fusion
16 {
17     struct nil_;
18 
19     struct cons_tag;
20 
21     template <typename Car, typename Cdr>
22     struct cons;
23 
24     template <typename Cons>
25     struct cons_iterator;
26 
27     namespace extension
28     {
29         template <typename Tag>
30         struct begin_impl;
31 
32         template <>
33         struct begin_impl<cons_tag>
34         {
35             template <typename Sequence>
36             struct apply
37             {
38                 typedef cons_iterator<Sequence> type;
39 
40                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
41                 static type
callboost::fusion::extension::begin_impl::apply42                 call(Sequence& t)
43                 {
44                     return type(t);
45                 }
46             };
47         };
48     }
49 }}
50 
51 #endif
52