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_CATEGORY_OF_07202005_0308)
8#define FUSION_CATEGORY_OF_07202005_0308
9
10#include <boost/fusion/support/config.hpp>
11#include <boost/fusion/support/tag_of.hpp>
12#include <boost/type_traits/is_base_of.hpp>
13
14namespace boost { namespace fusion
15{
16 // Special tags:
17 struct boost_tuple_tag; // boost::tuples::tuple tag
18 struct boost_array_tag; // boost::array tag
19 struct mpl_sequence_tag; // mpl sequence tag
20 struct std_pair_tag; // std::pair tag
21
22 struct incrementable_traversal_tag {};
23
24 struct single_pass_traversal_tag
25 : incrementable_traversal_tag {};
26
27 struct forward_traversal_tag
28 : single_pass_traversal_tag {};
29
30 struct bidirectional_traversal_tag
31 : forward_traversal_tag {};
32
33 struct random_access_traversal_tag
34 : bidirectional_traversal_tag {};
35
36 struct associative_tag {};
37
38 struct unbounded_tag {};
39
40 namespace extension
41 {
42 template<typename Tag>
43 struct category_of_impl
44 {
45 template<typename T>
46 struct apply
47 {
48 typedef typename T::category type;
49 };
50 };
51
52 template <>
53 struct category_of_impl<boost_tuple_tag>;
54
55 template <>
56 struct category_of_impl<boost_array_tag>;
57
58 template <>
59 struct category_of_impl<mpl_sequence_tag>;
60
61 template <>
62 struct category_of_impl<std_pair_tag>;
63 }
64
65 namespace traits
66 {
67 template <typename T>
68 struct category_of
69 : extension::category_of_impl<typename fusion::detail::tag_of<T>::type>::
70 template apply<T>
71 {};
72
73 template <typename T>
74 struct is_associative
75 : is_base_of<
76 associative_tag
77 , typename category_of<T>::type>
78 {};
79
80 template <typename T>
81 struct is_incrementable
82 : is_base_of<
83 incrementable_traversal_tag
84 , typename category_of<T>::type>
85 {};
86
87 template <typename T>
88 struct is_single_pass
89 : is_base_of<
90 single_pass_traversal_tag
91 , typename category_of<T>::type>
92 {};
93
94 template <typename T>
95 struct is_forward
96 : is_base_of<
97 forward_traversal_tag
98 , typename category_of<T>::type>
99 {};
100
101 template <typename T>
102 struct is_bidirectional
103 : is_base_of<
104 bidirectional_traversal_tag
105 , typename category_of<T>::type>
106 {};
107
108 template <typename T>
109 struct is_random_access
110 : is_base_of<
111 random_access_traversal_tag
112 , typename category_of<T>::type>
113 {};
114
115 template <typename T>
116 struct is_unbounded
117 : is_base_of<
118 unbounded_tag
119 , typename category_of<T>::type>
120 {};
121 }
122}}
123
124#endif
125

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