]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | /*! |
2 | @file | |
3 | Forward declares `boost::hana::symmetric_difference`. | |
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_FWD_SYMMETRIC_DIFFERENCE_HPP | |
11 | #define BOOST_HANA_FWD_SYMMETRIC_DIFFERENCE_HPP | |
12 | ||
13 | #include <boost/hana/config.hpp> | |
14 | #include <boost/hana/core/when.hpp> | |
15 | ||
16 | ||
17 | BOOST_HANA_NAMESPACE_BEGIN | |
18 | //! Returns the symmetric set-theoretic difference of two sets. | |
19 | //! @relates hana::set | |
20 | //! | |
21 | //! Given two sets `xs` and `ys`, `symmetric_difference(xs, ys)` is a new | |
22 | //! set containing all the elements of `xs` that are not contained in `ys`, | |
23 | //! and all the elements of `ys` that are not contained in `xs`. The | |
24 | //! symmetric difference of two sets satisfies the following: | |
25 | //! @code | |
26 | //! symmetric_difference(xs, ys) == union_(difference(xs, ys), difference(ys, xs)) | |
27 | //! @endcode | |
28 | //! | |
29 | //! | |
30 | //! @param xs, ys | |
31 | //! Two sets to compute the symmetric difference of. | |
32 | //! | |
33 | //! | |
34 | //! Example | |
35 | //! ------- | |
36 | //! @include example/symmetric_difference.cpp | |
37 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
38 | constexpr auto symmetric_difference = [](auto&& xs, auto&& ys) { | |
39 | return tag-dispatched; | |
40 | }; | |
41 | #else | |
42 | template <typename S, typename = void> | |
43 | struct symmetric_difference_impl : symmetric_difference_impl<S, when<true>> { }; | |
44 | ||
45 | struct symmetric_difference_t { | |
46 | template <typename Xs, typename Ys> | |
47 | constexpr auto operator()(Xs&& xs, Ys&& ys) const; | |
48 | }; | |
49 | ||
50 | constexpr symmetric_difference_t symmetric_difference{}; | |
51 | #endif | |
52 | BOOST_HANA_NAMESPACE_END | |
53 | ||
54 | #endif // !BOOST_HANA_FWD_SYMMETRIC_DIFFERENCE_HPP |