76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
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/*!
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@file
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Defines `boost::hana::unique`.
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@copyright Louis Dionne 2013-2016
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_HANA_UNIQUE_HPP
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#define BOOST_HANA_UNIQUE_HPP
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#include <boost/hana/fwd/unique.hpp>
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#include <boost/hana/concept/sequence.hpp>
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/dispatch.hpp>
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#include <boost/hana/detail/nested_by.hpp> // required by fwd decl
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#include <boost/hana/equal.hpp>
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#include <boost/hana/front.hpp>
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#include <boost/hana/group.hpp>
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#include <boost/hana/transform.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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//! @cond
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template <typename Xs>
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constexpr auto unique_t::operator()(Xs&& xs) const {
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using S = typename hana::tag_of<Xs>::type;
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using Unique = BOOST_HANA_DISPATCH_IF(unique_impl<S>,
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hana::Sequence<S>::value
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);
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#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
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static_assert(hana::Sequence<S>::value,
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"hana::unique(xs) requires 'xs' to be a Sequence");
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#endif
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return Unique::apply(static_cast<Xs&&>(xs));
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}
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template <typename Xs, typename Predicate>
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constexpr auto unique_t::operator()(Xs&& xs, Predicate&& predicate) const {
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using S = typename hana::tag_of<Xs>::type;
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using Unique = BOOST_HANA_DISPATCH_IF(unique_impl<S>,
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hana::Sequence<S>::value
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);
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#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
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static_assert(hana::Sequence<S>::value,
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"hana::unique(xs, predicate) requires 'xs' to be a Sequence");
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#endif
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return Unique::apply(static_cast<Xs&&>(xs),
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static_cast<Predicate&&>(predicate));
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}
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//! @endcond
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template <typename S, bool condition>
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struct unique_impl<S, when<condition>> : default_ {
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template <typename Xs, typename Pred>
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static constexpr auto apply(Xs&& xs, Pred&& pred) {
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return hana::transform(
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hana::group(static_cast<Xs&&>(xs), static_cast<Pred&&>(pred)),
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hana::front
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);
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}
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template <typename Xs>
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static constexpr auto apply(Xs&& xs)
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{ return unique_impl::apply(static_cast<Xs&&>(xs), hana::equal); }
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};
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_UNIQUE_HPP
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