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_IS_VIEW_03202006_0015) |
8 | #define FUSION_IS_VIEW_03202006_0015 |
9 | |
10 | #include <boost/fusion/support/config.hpp> |
11 | #include <boost/mpl/bool.hpp> |
12 | #include <boost/fusion/support/tag_of.hpp> |
13 | |
14 | namespace boost { namespace fusion |
15 | { |
16 | // Special tags: |
17 | struct non_fusion_tag; |
18 | struct sequence_facade_tag; |
19 | struct boost_tuple_tag; // boost::tuples::tuple tag |
20 | struct boost_array_tag; // boost::array tag |
21 | struct mpl_sequence_tag; // mpl sequence tag |
22 | struct std_pair_tag; // std::pair tag |
23 | |
24 | namespace extension |
25 | { |
26 | template<typename Tag> |
27 | struct is_view_impl |
28 | { |
29 | template <typename T> |
30 | struct apply |
31 | { |
32 | typedef typename T::is_view type; |
33 | }; |
34 | }; |
35 | |
36 | template <> |
37 | struct is_view_impl<non_fusion_tag> |
38 | { |
39 | template <typename T> |
40 | struct apply : mpl::false_ {}; |
41 | }; |
42 | |
43 | template <> |
44 | struct is_view_impl<sequence_facade_tag> |
45 | { |
46 | template <typename Sequence> |
47 | struct apply : Sequence::is_view {}; |
48 | }; |
49 | |
50 | template <> |
51 | struct is_view_impl<boost_tuple_tag>; |
52 | |
53 | template <> |
54 | struct is_view_impl<boost_array_tag>; |
55 | |
56 | template <> |
57 | struct is_view_impl<mpl_sequence_tag>; |
58 | |
59 | template <> |
60 | struct is_view_impl<std_pair_tag>; |
61 | } |
62 | |
63 | namespace traits |
64 | { |
65 | template <typename T> |
66 | struct is_view : |
67 | mpl::bool_< |
68 | (bool)extension::is_view_impl<typename fusion::detail::tag_of<T>::type>:: |
69 | template apply<T>::type::value |
70 | > |
71 | {}; |
72 | } |
73 | }} |
74 | |
75 | #endif |
76 |