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- /*!
- @file
- Defines `boost::hana::less_equal`.
- @copyright Louis Dionne 2013-2017
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
- */
- #ifndef BOOST_HANA_LESS_EQUAL_HPP
- #define BOOST_HANA_LESS_EQUAL_HPP
- #include <boost/hana/fwd/less_equal.hpp>
- #include <boost/hana/concept/orderable.hpp>
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/common.hpp>
- #include <boost/hana/core/to.hpp>
- #include <boost/hana/core/dispatch.hpp>
- #include <boost/hana/detail/has_common_embedding.hpp>
- #include <boost/hana/detail/nested_than.hpp> // required by fwd decl
- #include <boost/hana/less.hpp>
- #include <boost/hana/not.hpp>
- #include <type_traits>
- BOOST_HANA_NAMESPACE_BEGIN
- //! @cond
- template <typename X, typename Y>
- constexpr auto less_equal_t::operator()(X&& x, Y&& y) const {
- using T = typename hana::tag_of<X>::type;
- using U = typename hana::tag_of<Y>::type;
- using LessEqual = BOOST_HANA_DISPATCH_IF(
- decltype(less_equal_impl<T, U>{}),
- hana::Orderable<T>::value &&
- hana::Orderable<U>::value
- );
- #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
- static_assert(hana::Orderable<T>::value,
- "hana::less_equal(x, y) requires 'x' to be Orderable");
- static_assert(hana::Orderable<U>::value,
- "hana::less_equal(x, y) requires 'y' to be Orderable");
- #endif
- return LessEqual::apply(static_cast<X&&>(x), static_cast<Y&&>(y));
- }
- //! @endcond
- template <typename T, typename U, bool condition>
- struct less_equal_impl<T, U, when<condition>> : default_ {
- template <typename X, typename Y>
- static constexpr decltype(auto) apply(X&& x, Y&& y) {
- return hana::not_(hana::less(static_cast<Y&&>(y),
- static_cast<X&&>(x)));
- }
- };
- // Cross-type overload
- template <typename T, typename U>
- struct less_equal_impl<T, U, when<
- detail::has_nontrivial_common_embedding<Orderable, T, U>::value
- >> {
- using C = typename hana::common<T, U>::type;
- template <typename X, typename Y>
- static constexpr decltype(auto) apply(X&& x, Y&& y) {
- return hana::less_equal(hana::to<C>(static_cast<X&&>(x)),
- hana::to<C>(static_cast<Y&&>(y)));
- }
- };
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_LESS_EQUAL_HPP
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