| /*============================================================================= |
| Copyright (c) 2001-2006 Joel de Guzman |
| Copyright (c) 2005-2006 Dan Marsden |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #if !defined(BOOST_FUSION_AT_KEY_IMPL_20060223_2017) |
| #define BOOST_FUSION_AT_KEY_IMPL_20060223_2017 |
| |
| #include <string> |
| #include <boost/mpl/if.hpp> |
| #include <boost/type_traits/is_const.hpp> |
| |
| namespace fields |
| { |
| struct name; |
| struct age; |
| } |
| |
| namespace example |
| { |
| struct example_sequence_tag; |
| } |
| |
| namespace boost { namespace fusion { |
| |
| namespace extension |
| { |
| template<typename Tag> |
| struct at_key_impl; |
| |
| template<> |
| struct at_key_impl<example::example_sequence_tag> |
| { |
| template<typename Sequence, typename Key> |
| struct apply; |
| |
| template<typename Sequence> |
| struct apply<Sequence, fields::name> |
| { |
| typedef typename mpl::if_< |
| is_const<Sequence>, |
| std::string const&, |
| std::string&>::type type; |
| |
| static type |
| call(Sequence& seq) |
| { |
| return seq.name; |
| }; |
| }; |
| |
| template<typename Sequence> |
| struct apply<Sequence, fields::age> |
| { |
| typedef typename mpl::if_< |
| is_const<Sequence>, |
| int const&, |
| int&>::type type; |
| |
| static type |
| call(Sequence& seq) |
| { |
| return seq.age; |
| }; |
| }; |
| }; |
| } |
| }} |
| |
| #endif |