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1 | /*! |
2 | @file | |
3 | Defines `boost::hana::not_equal`. | |
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_NOT_EQUAL_HPP | |
11 | #define BOOST_HANA_NOT_EQUAL_HPP | |
12 | ||
13 | #include <boost/hana/fwd/not_equal.hpp> | |
14 | ||
15 | #include <boost/hana/concept/comparable.hpp> | |
16 | #include <boost/hana/config.hpp> | |
17 | #include <boost/hana/core/to.hpp> | |
18 | #include <boost/hana/core/dispatch.hpp> | |
19 | #include <boost/hana/detail/has_common_embedding.hpp> | |
20 | #include <boost/hana/detail/nested_to.hpp> // required by fwd decl | |
21 | #include <boost/hana/equal.hpp> | |
22 | #include <boost/hana/not.hpp> | |
23 | ||
24 | ||
25 | BOOST_HANA_NAMESPACE_BEGIN | |
26 | //! @cond | |
27 | template <typename X, typename Y> | |
28 | constexpr auto not_equal_t::operator()(X&& x, Y&& y) const { | |
29 | using T = typename hana::tag_of<X>::type; | |
30 | using U = typename hana::tag_of<Y>::type; | |
31 | using NotEqual = not_equal_impl<T, U>; | |
32 | return NotEqual::apply(static_cast<X&&>(x), static_cast<Y&&>(y)); | |
33 | } | |
34 | //! @endcond | |
35 | ||
36 | template <typename T, typename U, bool condition> | |
37 | struct not_equal_impl<T, U, when<condition>> : default_ { | |
38 | template <typename X, typename Y> | |
39 | static constexpr decltype(auto) apply(X&& x, Y&& y) { | |
40 | return hana::not_(hana::equal(static_cast<X&&>(x), | |
41 | static_cast<Y&&>(y))); | |
42 | } | |
43 | }; | |
44 | ||
45 | // Cross-type overload | |
46 | template <typename T, typename U> | |
47 | struct not_equal_impl<T, U, when< | |
48 | detail::has_nontrivial_common_embedding<Comparable, T, U>::value | |
49 | >> { | |
50 | using C = typename hana::common<T, U>::type; | |
51 | template <typename X, typename Y> | |
52 | static constexpr decltype(auto) apply(X&& x, Y&& y) { | |
53 | return hana::not_equal(hana::to<C>(static_cast<X&&>(x)), | |
54 | hana::to<C>(static_cast<Y&&>(y))); | |
55 | } | |
56 | }; | |
57 | BOOST_HANA_NAMESPACE_END | |
58 | ||
59 | #endif // !BOOST_HANA_NOT_EQUAL_HPP |