| 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_PRIOR_05042005_1144) |
| 8 | #define FUSION_PRIOR_05042005_1144 |
| 9 | |
| 10 | #include <boost/fusion/support/config.hpp> |
| 11 | #include <boost/fusion/support/tag_of.hpp> |
| 12 | |
| 13 | namespace boost { namespace fusion |
| 14 | { |
| 15 | // Special tags: |
| 16 | struct iterator_facade_tag; // iterator facade tag |
| 17 | struct boost_array_iterator_tag; // boost::array iterator tag |
| 18 | struct mpl_iterator_tag; // mpl sequence iterator tag |
| 19 | struct std_pair_iterator_tag; // std::pair iterator tag |
| 20 | |
| 21 | namespace extension |
| 22 | { |
| 23 | template <typename Tag> |
| 24 | struct prior_impl |
| 25 | { |
| 26 | template <typename Iterator> |
| 27 | struct apply {}; |
| 28 | }; |
| 29 | |
| 30 | template <> |
| 31 | struct prior_impl<iterator_facade_tag> |
| 32 | { |
| 33 | template <typename Iterator> |
| 34 | struct apply : Iterator::template prior<Iterator> {}; |
| 35 | }; |
| 36 | |
| 37 | template <> |
| 38 | struct prior_impl<boost_array_iterator_tag>; |
| 39 | |
| 40 | template <> |
| 41 | struct prior_impl<mpl_iterator_tag>; |
| 42 | |
| 43 | template <> |
| 44 | struct prior_impl<std_pair_iterator_tag>; |
| 45 | } |
| 46 | |
| 47 | namespace result_of |
| 48 | { |
| 49 | template <typename Iterator> |
| 50 | struct prior |
| 51 | : extension::prior_impl<typename detail::tag_of<Iterator>::type>:: |
| 52 | template apply<Iterator> |
| 53 | {}; |
| 54 | } |
| 55 | |
| 56 | template <typename Iterator> |
| 57 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED |
| 58 | inline typename result_of::prior<Iterator>::type const |
| 59 | prior(Iterator const& i) |
| 60 | { |
| 61 | return result_of::prior<Iterator>::call(i); |
| 62 | } |
| 63 | }} |
| 64 | |
| 65 | #endif |
| 66 |