1 /*!
2 @file
3 Defines `boost::hana::not_equal`.
4 
5 @copyright Louis Dionne 2013-2017
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>
operator ()(X && x,Y && y) const28     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>
applynot_equal_impl39         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>
applynot_equal_impl52         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
60