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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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