1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3     Copyright (c) 2007 Tobias Schwinger
4 
5     Distributed under the Boost Software License, Version 1.0. (See accompanying
6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 ==============================================================================*/
8 #if !defined(FUSION_SEQUENCE_BASE_04182005_0737)
9 #define FUSION_SEQUENCE_BASE_04182005_0737
10 
11 #include <boost/config.hpp>
12 #include <boost/fusion/support/config.hpp>
13 #include <boost/mpl/begin_end_fwd.hpp>
14 
15 namespace boost { namespace fusion
16 {
17     namespace detail
18     {
19         struct from_sequence_convertible_type
20         {};
21     }
22 
23     template <typename Sequence>
24     struct sequence_base
25     {
26         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
27         Sequence const&
derivedboost::fusion::sequence_base28         derived() const BOOST_NOEXCEPT
29         {
30             return static_cast<Sequence const&>(*this);
31         }
32 
33         BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
34         Sequence&
derivedboost::fusion::sequence_base35         derived() BOOST_NOEXCEPT
36         {
37             return static_cast<Sequence&>(*this);
38         }
39 
40         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
operator detail::from_sequence_convertible_typeboost::fusion::sequence_base41         operator detail::from_sequence_convertible_type() const BOOST_NOEXCEPT
42         {
43             return detail::from_sequence_convertible_type();
44         }
45     };
46 
47     struct fusion_sequence_tag;
48 }}
49 
50 namespace boost { namespace mpl
51 {
52     // Deliberately break mpl::begin, so it doesn't lie that a Fusion sequence
53     // is not an MPL sequence by returning mpl::void_.
54     // In other words: Fusion Sequences are always MPL Sequences, but they can
55     // be incompletely defined.
56     template<> struct begin_impl< boost::fusion::fusion_sequence_tag >;
57 }}
58 
59 #endif
60