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_SEQUENCE_05052005_1002)
8 #define FUSION_IS_SEQUENCE_05052005_1002
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/fusion/support/sequence_base.hpp>
12 #include <boost/fusion/support/tag_of.hpp>
13 #include <boost/mpl/is_sequence.hpp>
14 #include <boost/mpl/or.hpp>
15 #include <boost/mpl/bool.hpp>
16 #include <boost/type_traits/is_convertible.hpp>
17 #include <boost/type_traits/is_same.hpp>
18 
19 namespace boost { namespace fusion
20 {
21     // Special tags:
22     struct non_fusion_tag;
23     struct boost_tuple_tag; // boost::tuples::tuple tag
24     struct boost_array_tag; // boost::array tag
25     struct mpl_sequence_tag; // mpl sequence tag
26     struct std_pair_tag; // std::pair tag
27 
28     namespace extension
29     {
30         template <typename T>
31         struct is_sequence_impl
32         {
33             template <typename Sequence>
34             struct apply
35               : is_convertible<Sequence, fusion::detail::from_sequence_convertible_type>
36             {};
37         };
38 
39         template <>
40         struct is_sequence_impl<non_fusion_tag>
41         {
42             template <typename T>
43             struct apply : mpl::false_ {};
44         };
45 
46         template <>
47         struct is_sequence_impl<boost_tuple_tag>;
48 
49         template <>
50         struct is_sequence_impl<boost_array_tag>;
51 
52         template <>
53         struct is_sequence_impl<mpl_sequence_tag>;
54 
55         template <>
56         struct is_sequence_impl<std_pair_tag>;
57     }
58 
59     namespace traits
60     {
61         template <typename T>
62         struct is_sequence
63           : mpl::bool_<
64                 (bool)extension::is_sequence_impl<
65                     typename fusion::detail::tag_of<T>::type
66                 >::template apply<T>::type::value
67             >
68         {};
69 
70         template <typename Sequence, typename Enable = void>
71         struct is_native_fusion_sequence
72           : is_convertible<Sequence, fusion::detail::from_sequence_convertible_type>
73         {};
74     }
75 }}
76 
77 #endif
78