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/*!
@file
Defines `boost::hana::remove`.
@copyright Louis Dionne 2013-2016
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_REMOVE_HPP
#define BOOST_HANA_REMOVE_HPP
#include <boost/hana/fwd/remove.hpp>
#include <boost/hana/concept/monad_plus.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/core/dispatch.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/filter.hpp>
#include <boost/hana/functional/compose.hpp>
#include <boost/hana/not.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! @cond
template <typename Xs, typename Value>
constexpr auto remove_t::operator()(Xs&& xs, Value&& value) const {
using M = typename hana::tag_of<Xs>::type;
using Remove = BOOST_HANA_DISPATCH_IF(remove_impl<M>,
hana::MonadPlus<M>::value
);
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
static_assert(hana::MonadPlus<M>::value,
"hana::remove(xs, value) requires 'xs' to be a MonadPlus");
#endif
return Remove::apply(static_cast<Xs&&>(xs),
static_cast<Value&&>(value));
}
//! @endcond
template <typename M, bool condition>
struct remove_impl<M, when<condition>> : default_ {
template <typename Xs, typename Value>
static constexpr auto apply(Xs&& xs, Value&& value) {
return hana::filter(static_cast<Xs&&>(xs),
hana::compose(hana::not_,
hana::equal.to(static_cast<Value&&>(value))));
}
};
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_REMOVE_HPP
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