| 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_DEREF_IMPL_07172005_0831) |
| 9 | #define FUSION_DEREF_IMPL_07172005_0831 |
| 10 | |
| 11 | #include <boost/fusion/support/config.hpp> |
| 12 | #include <boost/mpl/eval_if.hpp> |
| 13 | #include <boost/type_traits/is_const.hpp> |
| 14 | #include <boost/type_traits/add_const.hpp> |
| 15 | #include <boost/type_traits/add_reference.hpp> |
| 16 | |
| 17 | namespace boost { namespace fusion |
| 18 | { |
| 19 | struct cons_iterator_tag; |
| 20 | |
| 21 | namespace extension |
| 22 | { |
| 23 | template <typename Tag> |
| 24 | struct deref_impl; |
| 25 | |
| 26 | template <> |
| 27 | struct deref_impl<cons_iterator_tag> |
| 28 | { |
| 29 | template <typename Iterator> |
| 30 | struct apply |
| 31 | { |
| 32 | typedef typename Iterator::cons_type cons_type; |
| 33 | typedef typename cons_type::car_type value_type; |
| 34 | |
| 35 | typedef typename mpl::eval_if< |
| 36 | is_const<cons_type> |
| 37 | , add_reference<typename add_const<value_type>::type> |
| 38 | , add_reference<value_type> >::type |
| 39 | type; |
| 40 | |
| 41 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED |
| 42 | static type |
| 43 | call(Iterator const& i) |
| 44 | { |
| 45 | return i.cons.car; |
| 46 | } |
| 47 | }; |
| 48 | }; |
| 49 | } |
| 50 | }} |
| 51 | |
| 52 | #endif |
| 53 | |
| 54 | |
| 55 |