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