]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | /*! |
2 | @file | |
3 | Adapts `boost::fusion::list` for use with Hana. | |
4 | ||
b32b8144 | 5 | @copyright Louis Dionne 2013-2017 |
7c673cae FG |
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_LIST_HPP | |
11 | #define BOOST_HANA_EXT_BOOST_FUSION_LIST_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_list.hpp> | |
24 | #include <boost/fusion/container/list.hpp> | |
25 | #include <boost/fusion/container/list/convert.hpp> | |
26 | #include <boost/fusion/support/tag_of.hpp> | |
27 | #include <boost/version.hpp> | |
28 | ||
29 | #include <cstddef> | |
30 | #include <type_traits> | |
31 | #include <utility> | |
32 | ||
33 | ||
34 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
35 | namespace boost { namespace fusion { | |
36 | //! @ingroup group-ext-fusion | |
37 | //! Adapter for Boost.Fusion lists. | |
38 | //! | |
39 | //! | |
40 | //! Modeled concepts | |
41 | //! ---------------- | |
42 | //! A Fusion list is a model of the `Sequence` concept, and all the | |
43 | //! concepts it refines. That makes it essentially the same as a Hana | |
44 | //! tuple, although the complexity of some operations might differ from | |
45 | //! that of a tuple. | |
46 | //! | |
47 | //! @include example/ext/boost/fusion/list.cpp | |
48 | template <typename ...T> | |
49 | struct list { }; | |
50 | }} | |
51 | #endif | |
52 | ||
53 | ||
54 | BOOST_HANA_NAMESPACE_BEGIN | |
55 | namespace ext { namespace boost { namespace fusion { | |
56 | struct list_tag; | |
57 | }}} | |
58 | ||
59 | template <typename T> | |
60 | struct tag_of<T, when< | |
61 | std::is_same< | |
62 | typename ::boost::fusion::traits::tag_of<T>::type, | |
63 | ::boost::fusion::traits::tag_of< | |
64 | ::boost::fusion::list<> | |
65 | >::type | |
66 | >::value | |
67 | >> { | |
68 | using type = ext::boost::fusion::list_tag; | |
69 | }; | |
70 | ||
71 | namespace detail { | |
72 | template <> | |
73 | struct is_fusion_sequence<ext::boost::fusion::list_tag> { | |
74 | static constexpr bool value = true; | |
75 | }; | |
76 | } | |
77 | ||
78 | ////////////////////////////////////////////////////////////////////////// | |
79 | // Iterable (the rest is in detail/common.hpp) | |
80 | ////////////////////////////////////////////////////////////////////////// | |
81 | template <> | |
82 | struct drop_front_impl<ext::boost::fusion::list_tag> { | |
83 | template <std::size_t n, typename Xs, std::size_t ...i> | |
84 | static constexpr auto drop_front_helper(Xs&& xs, std::index_sequence<i...>) { | |
85 | return hana::make<ext::boost::fusion::list_tag>( | |
86 | hana::at_c<n + i>(static_cast<Xs&&>(xs))... | |
87 | ); | |
88 | } | |
89 | ||
90 | template <typename Xs, typename N> | |
91 | static constexpr auto apply(Xs&& xs, N const&) { | |
92 | constexpr std::size_t n = N::value; | |
93 | constexpr std::size_t len = decltype(hana::length(xs))::value; | |
94 | return drop_front_helper<n>(static_cast<Xs&&>(xs), | |
95 | std::make_index_sequence<(n < len ? len - n : 0)>{}); | |
96 | } | |
97 | }; | |
98 | ||
99 | ////////////////////////////////////////////////////////////////////////// | |
100 | // Sequence | |
101 | ////////////////////////////////////////////////////////////////////////// | |
102 | template <> | |
103 | struct make_impl<ext::boost::fusion::list_tag> { | |
104 | template <typename ...Xs> | |
105 | static constexpr auto apply(Xs&& ...xs) { | |
106 | return ::boost::fusion::make_list(static_cast<Xs&&>(xs)...); | |
107 | } | |
108 | }; | |
109 | BOOST_HANA_NAMESPACE_END | |
110 | ||
111 | #endif // !BOOST_HANA_EXT_BOOST_FUSION_LIST_HPP |