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- /*!
- @file
- Defines `boost::hana::min`.
- @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_MIN_HPP
- #define BOOST_HANA_MIN_HPP
- #include <boost/hana/fwd/min.hpp>
- #include <boost/hana/concept/orderable.hpp>
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/dispatch.hpp>
- #include <boost/hana/if.hpp>
- #include <boost/hana/less.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- //! @cond
- template <typename X, typename Y>
- constexpr decltype(auto) min_t::operator()(X&& x, Y&& y) const {
- using T = typename hana::tag_of<X>::type;
- using U = typename hana::tag_of<Y>::type;
- using Min = BOOST_HANA_DISPATCH_IF(decltype(min_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::min(x, y) requires 'x' to be Orderable");
- static_assert(hana::Orderable<U>::value,
- "hana::min(x, y) requires 'y' to be Orderable");
- #endif
- return Min::apply(static_cast<X&&>(x), static_cast<Y&&>(y));
- }
- //! @endcond
- template <typename T, typename U, bool condition>
- struct min_impl<T, U, when<condition>> : default_ {
- template <typename X, typename Y>
- static constexpr decltype(auto) apply(X&& x, Y&& y) {
- decltype(auto) cond = hana::less(x, y);
- return hana::if_(static_cast<decltype(cond)&&>(cond),
- static_cast<X&&>(x),
- static_cast<Y&&>(y)
- );
- }
- };
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_MIN_HPP
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