]>
Commit | Line | Data |
---|---|---|
1 | /*! | |
2 | @file | |
3 | Adapts `boost::fusion::vector` for use with Hana. | |
4 | ||
5 | @copyright Louis Dionne 2013-2016 | |
6 | Distributed under the Boost Software License, Version 1.0. | |
7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_EXT_BOOST_FUSION_VECTOR_HPP | |
11 | #define BOOST_HANA_EXT_BOOST_FUSION_VECTOR_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | #include <boost/hana/core/when.hpp> | |
15 | #include <boost/hana/ext/boost/fusion/detail/common.hpp> | |
16 | #include <boost/hana/fwd/at.hpp> | |
17 | #include <boost/hana/fwd/core/make.hpp> | |
18 | #include <boost/hana/fwd/core/tag_of.hpp> | |
19 | #include <boost/hana/fwd/drop_front.hpp> | |
20 | #include <boost/hana/fwd/length.hpp> | |
21 | ||
22 | #include <boost/fusion/algorithm/transformation/pop_front.hpp> | |
23 | #include <boost/fusion/container/generation/make_vector.hpp> | |
24 | #include <boost/fusion/container/vector.hpp> | |
25 | #include <boost/fusion/container/vector/convert.hpp> | |
26 | #include <boost/fusion/support/tag_of.hpp> | |
27 | ||
28 | #include <cstddef> | |
29 | #include <type_traits> | |
30 | #include <utility> | |
31 | ||
32 | ||
33 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
34 | namespace boost { namespace fusion { | |
35 | //! @ingroup group-ext-fusion | |
36 | //! Adapter for Boost.Fusion vectors. | |
37 | //! | |
38 | //! | |
39 | //! Modeled concepts | |
40 | //! ---------------- | |
41 | //! A Fusion vector is a model of the `Sequence` concept, and all the | |
42 | //! concepts it refines. That makes it essentially the same as a Hana | |
43 | //! tuple, although the complexity of some operations might differ from | |
44 | //! that of a tuple. | |
45 | //! | |
46 | //! @include example/ext/boost/fusion/vector.cpp | |
47 | template <typename ...T> | |
48 | struct vector { }; | |
49 | }} | |
50 | #endif | |
51 | ||
52 | ||
53 | BOOST_HANA_NAMESPACE_BEGIN | |
54 | namespace ext { namespace boost { namespace fusion { | |
55 | struct vector_tag; | |
56 | }}} | |
57 | ||
58 | template <typename T> | |
59 | struct tag_of<T, when< | |
60 | std::is_same< | |
61 | typename ::boost::fusion::traits::tag_of<T>::type, | |
62 | ::boost::fusion::traits::tag_of< | |
63 | ::boost::fusion::vector<> | |
64 | >::type | |
65 | >::value | |
66 | >> { | |
67 | using type = ext::boost::fusion::vector_tag; | |
68 | }; | |
69 | ||
70 | namespace detail { | |
71 | template <> | |
72 | struct is_fusion_sequence<ext::boost::fusion::vector_tag> { | |
73 | static constexpr bool value = true; | |
74 | }; | |
75 | } | |
76 | ||
77 | ////////////////////////////////////////////////////////////////////////// | |
78 | // Iterable (the rest is in detail/common.hpp) | |
79 | ////////////////////////////////////////////////////////////////////////// | |
80 | template <> | |
81 | struct drop_front_impl<ext::boost::fusion::vector_tag> { | |
82 | template <std::size_t n, typename Xs, std::size_t ...i> | |
83 | static constexpr auto drop_front_helper(Xs&& xs, std::index_sequence<i...>) { | |
84 | return hana::make<ext::boost::fusion::vector_tag>( | |
85 | hana::at_c<n + i>(static_cast<Xs&&>(xs))... | |
86 | ); | |
87 | } | |
88 | ||
89 | template <typename Xs, typename N> | |
90 | static constexpr auto apply(Xs&& xs, N const&) { | |
91 | constexpr std::size_t n = N::value; | |
92 | constexpr std::size_t len = decltype(hana::length(xs))::value; | |
93 | return drop_front_helper<n>(static_cast<Xs&&>(xs), | |
94 | std::make_index_sequence<(n < len ? len - n : 0)>{}); | |
95 | } | |
96 | }; | |
97 | ||
98 | ////////////////////////////////////////////////////////////////////////// | |
99 | // Sequence | |
100 | ////////////////////////////////////////////////////////////////////////// | |
101 | template <> | |
102 | struct make_impl<ext::boost::fusion::vector_tag> { | |
103 | template <typename ...Xs> | |
104 | static constexpr auto apply(Xs&& ...xs) { | |
105 | return ::boost::fusion::make_vector(static_cast<Xs&&>(xs)...); | |
106 | } | |
107 | }; | |
108 | BOOST_HANA_NAMESPACE_END | |
109 | ||
110 | #endif // !BOOST_HANA_EXT_BOOST_FUSION_VECTOR_HPP |