1 /*=============================================================================
2     Copyright (c) 2009 Christopher Schmidt
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 #ifndef BOOST_FUSION_ITERATOR_KEY_OF_HPP
9 #define BOOST_FUSION_ITERATOR_KEY_OF_HPP
10 
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/fusion/support/tag_of.hpp>
13 
14 namespace boost { namespace fusion
15 {
16     struct iterator_facade_tag;
17 
18     namespace extension
19     {
20         template <typename>
21         struct key_of_impl;
22 
23         template <>
24         struct key_of_impl<iterator_facade_tag>
25         {
26             template <typename It>
27             struct apply
28               : It::template key_of<It>
29             {};
30         };
31     }
32 
33     namespace result_of
34     {
35         template <typename It>
36         struct key_of
37           : extension::key_of_impl<typename traits::tag_of<It>::type>::
38                 template apply<It>
39         {};
40     }
41 }}
42 
43 #endif
44