detail/operators/orderable.hpp

0001 /*!
0002 @file
0003 Defines operators for Orderables.
0004
0005 Copyright Louis Dionne 2013-2022
0006 Distributed under the Boost Software License, Version 1.0.
0007 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
0008  */
0009
0010 #ifndef BOOST_HANA_DETAIL_OPERATORS_ORDERABLE_HPP
0011 #define BOOST_HANA_DETAIL_OPERATORS_ORDERABLE_HPP
0012
0013 #include <boost/hana/config.hpp>
0014 #include <boost/hana/core/tag_of.hpp>
0015 #include <boost/hana/fwd/greater.hpp>
0016 #include <boost/hana/fwd/greater_equal.hpp>
0017 #include <boost/hana/fwd/less.hpp>
0018 #include <boost/hana/fwd/less_equal.hpp>
0019
0020 #include <type_traits>
0021
0022
0023 namespace boost { namespace hana { namespace detail {
0024     template <typename Tag>
0025     struct orderable_operators {
0026         static constexpr bool value = false;
0027     };
0028
0029     namespace operators {
0030         template <typename X, typename Y, typename = typename std::enable_if<
0031             detail::orderable_operators<typename hana::tag_of<X>::type>::value ||
0032             detail::orderable_operators<typename hana::tag_of<Y>::type>::value
0033         >::type>
0034         constexpr auto operator<(X&& x, Y&& y)
0035         { return hana::less(static_cast<X&&>(x), static_cast<Y&&>(y)); }
0036
0037         template <typename X, typename Y, typename = typename std::enable_if<
0038             detail::orderable_operators<typename hana::tag_of<X>::type>::value ||
0039             detail::orderable_operators<typename hana::tag_of<Y>::type>::value
0040         >::type>
0041         constexpr auto operator>(X&& x, Y&& y)
0042         { return hana::greater(static_cast<X&&>(x), static_cast<Y&&>(y)); }
0043
0044         template <typename X, typename Y, typename = typename std::enable_if<
0045             detail::orderable_operators<typename hana::tag_of<X>::type>::value ||
0046             detail::orderable_operators<typename hana::tag_of<Y>::type>::value
0047         >::type>
0048         constexpr auto operator<=(X&& x, Y&& y)
0049         { return hana::less_equal(static_cast<X&&>(x), static_cast<Y&&>(y)); }
0050
0051         template <typename X, typename Y, typename = typename std::enable_if<
0052             detail::orderable_operators<typename hana::tag_of<X>::type>::value ||
0053             detail::orderable_operators<typename hana::tag_of<Y>::type>::value
0054         >::type>
0055         constexpr auto operator>=(X&& x, Y&& y)
0056         { return hana::greater_equal(static_cast<X&&>(x), static_cast<Y&&>(y)); }
0057     } // end namespace operators
0058 } }} // end namespace boost::hana
0059
0060 #endif // !BOOST_HANA_DETAIL_OPERATORS_ORDERABLE_HPP