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- /*!
- @file
- Defines `boost::hana::contains` and `boost::hana::in`.
- @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_CONTAINS_HPP
- #define BOOST_HANA_CONTAINS_HPP
- #include <boost/hana/fwd/contains.hpp>
- #include <boost/hana/any_of.hpp>
- #include <boost/hana/concept/searchable.hpp>
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/dispatch.hpp>
- #include <boost/hana/equal.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- //! @cond
- template <typename Xs, typename Key>
- constexpr auto contains_t::operator()(Xs&& xs, Key&& key) const {
- using S = typename hana::tag_of<Xs>::type;
- using Contains = BOOST_HANA_DISPATCH_IF(contains_impl<S>,
- hana::Searchable<S>::value
- );
- #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
- static_assert(hana::Searchable<S>::value,
- "hana::contains(xs, key) requires 'xs' to be a Searchable");
- #endif
- return Contains::apply(static_cast<Xs&&>(xs),
- static_cast<Key&&>(key));
- }
- //! @endcond
- template <typename S, bool condition>
- struct contains_impl<S, when<condition>> : default_ {
- template <typename Xs, typename X>
- static constexpr auto apply(Xs&& xs, X&& x) {
- return hana::any_of(static_cast<Xs&&>(xs),
- hana::equal.to(static_cast<X&&>(x)));
- }
- };
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_CONTAINS_HPP
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