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_AT_IMPL_05042005_0741)
8 #define FUSION_AT_IMPL_05042005_0741
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/fusion/support/detail/access.hpp>
12 #include <boost/fusion/container/vector/detail/value_at_impl.hpp>
13 #include <boost/static_assert.hpp>
14 
15 namespace boost { namespace fusion
16 {
17     struct vector_tag;
18 
19     namespace extension
20     {
21         template <typename Tag>
22         struct at_impl;
23 
24         template <>
25         struct at_impl<vector_tag>
26         {
27             template <typename Sequence, typename N>
28             struct apply
29             {
30                 typedef typename value_at_impl<vector_tag>::template apply<Sequence, N>::type element;
31                 typedef typename detail::ref_result<element>::type type;
32 
33                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
34                 static type
callboost::fusion::extension::at_impl::apply35                 call(Sequence& v)
36                 {
37                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
38                     return v.at_impl(N());
39                 }
40             };
41 
42             template <typename Sequence, typename N>
43             struct apply <Sequence const, N>
44             {
45                 typedef typename value_at_impl<vector_tag>::template apply<Sequence, N>::type element;
46                 typedef typename detail::cref_result<element>::type type;
47 
48                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
49                 static type
callboost::fusion::extension::at_impl::apply50                 call(Sequence const& v)
51                 {
52                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
53                     return v.at_impl(N());
54                 }
55             };
56         };
57     }
58 }}
59 
60 #endif
61