| 1 | /*============================================================================= |
|---|---|
| 2 | Copyright (c) 2011 Eric Niebler |
| 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 | |
| 8 | #if !defined(BOOST_FUSION_SINGLE_VIEW_VALUE_AT_IMPL_JUL_07_2011_1348PM) |
| 9 | #define BOOST_FUSION_SINGLE_VIEW_VALUE_AT_IMPL_JUL_07_2011_1348PM |
| 10 | |
| 11 | #include <boost/fusion/support/config.hpp> |
| 12 | #include <boost/mpl/int.hpp> |
| 13 | #include <boost/mpl/assert.hpp> |
| 14 | #include <boost/mpl/equal_to.hpp> |
| 15 | #include <boost/fusion/sequence/intrinsic/value_at.hpp> |
| 16 | |
| 17 | namespace boost { namespace fusion |
| 18 | { |
| 19 | struct single_view_tag; |
| 20 | |
| 21 | namespace extension |
| 22 | { |
| 23 | template<typename Tag> |
| 24 | struct value_at_impl; |
| 25 | |
| 26 | template<> |
| 27 | struct value_at_impl<single_view_tag> |
| 28 | { |
| 29 | template<typename Sequence, typename N> |
| 30 | struct apply |
| 31 | { |
| 32 | BOOST_MPL_ASSERT((mpl::equal_to<N, mpl::int_<0> >)); |
| 33 | typedef typename Sequence::value_type type; |
| 34 | }; |
| 35 | }; |
| 36 | } |
| 37 | |
| 38 | }} |
| 39 | |
| 40 | #endif |
| 41 |