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_BEGIN_04052005_1132) |
8 | #define FUSION_BEGIN_04052005_1132 |
9 | |
10 | #include <boost/fusion/support/config.hpp> |
11 | #include <boost/utility/enable_if.hpp> |
12 | #include <boost/mpl/empty_base.hpp> |
13 | #include <boost/mpl/if.hpp> |
14 | #include <boost/fusion/sequence/intrinsic_fwd.hpp> |
15 | #include <boost/fusion/support/tag_of.hpp> |
16 | #include <boost/fusion/support/is_sequence.hpp> |
17 | #include <boost/fusion/support/is_segmented.hpp> |
18 | #include <boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp> |
19 | |
20 | namespace boost { namespace fusion |
21 | { |
22 | // Special tags: |
23 | struct sequence_facade_tag; // iterator facade tag |
24 | struct boost_tuple_tag; // boost::tuples::tuple tag |
25 | struct boost_array_tag; // boost::array tag |
26 | struct mpl_sequence_tag; // mpl sequence tag |
27 | struct std_pair_tag; // std::pair tag |
28 | |
29 | namespace extension |
30 | { |
31 | template <typename Tag> |
32 | struct begin_impl |
33 | { |
34 | template <typename Sequence> |
35 | struct apply |
36 | : mpl::if_< |
37 | traits::is_segmented<Sequence> |
38 | , detail::segmented_begin<Sequence> |
39 | , mpl::empty_base |
40 | >::type |
41 | {}; |
42 | }; |
43 | |
44 | template <> |
45 | struct begin_impl<sequence_facade_tag> |
46 | { |
47 | template <typename Sequence> |
48 | struct apply : Sequence::template begin<Sequence> {}; |
49 | }; |
50 | |
51 | template <> |
52 | struct begin_impl<boost_tuple_tag>; |
53 | |
54 | template <> |
55 | struct begin_impl<boost_array_tag>; |
56 | |
57 | template <> |
58 | struct begin_impl<mpl_sequence_tag>; |
59 | |
60 | template <> |
61 | struct begin_impl<std_pair_tag>; |
62 | } |
63 | |
64 | namespace result_of |
65 | { |
66 | template <typename Sequence> |
67 | struct begin |
68 | : extension::begin_impl<typename detail::tag_of<Sequence>::type>:: |
69 | template apply<Sequence> |
70 | {}; |
71 | } |
72 | |
73 | template <typename Sequence> |
74 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED |
75 | inline typename |
76 | lazy_enable_if< |
77 | traits::is_sequence<Sequence> |
78 | , result_of::begin<Sequence> |
79 | >::type const |
80 | begin(Sequence& seq) |
81 | { |
82 | return result_of::begin<Sequence>::call(seq); |
83 | } |
84 | |
85 | template <typename Sequence> |
86 | BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED |
87 | inline typename |
88 | lazy_enable_if< |
89 | traits::is_sequence<Sequence> |
90 | , result_of::begin<Sequence const> |
91 | >::type const |
92 | begin(Sequence const& seq) |
93 | { |
94 | return result_of::begin<Sequence const>::call(seq); |
95 | } |
96 | }} |
97 | |
98 | #endif |
99 |