1 /*=============================================================================
2 Copyright (c) 2005-2012 Joel de Guzman
3 Copyright (c) 2005-2006 Dan Marsden
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(BOOST_FUSION_DEQUE_VALUE_AT_IMPL_08122006_0756)
9 #define BOOST_FUSION_DEQUE_VALUE_AT_IMPL_08122006_0756
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/fusion/container/deque/detail/keyed_element.hpp>
14 #include <boost/mpl/equal_to.hpp>
15 #include <boost/mpl/assert.hpp>
17 namespace boost { namespace fusion
27 struct value_at_impl<deque_tag>
29 template<typename Sequence, typename N>
32 typedef typename Sequence::next_up next_up;
33 typedef typename Sequence::next_down next_down;
34 BOOST_MPL_ASSERT_RELATION(next_down::value, !=, next_up::value);
36 static int const offset = next_down::value + 1;
37 typedef mpl::int_<(N::value + offset)> adjusted_index;
39 detail::keyed_element_value_at<Sequence, adjusted_index>::type