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
14namespace 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

source code of include/boost/fusion/support/is_view.hpp