65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
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/*!
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@file
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Defines `boost::hana::insert_range`.
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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_INSERT_RANGE_HPP
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#define BOOST_HANA_INSERT_RANGE_HPP
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#include <boost/hana/fwd/insert_range.hpp>
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#include <boost/hana/concat.hpp>
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#include <boost/hana/concept/foldable.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/to.hpp>
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#include <boost/hana/core/dispatch.hpp>
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#include <boost/hana/drop_front.hpp>
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#include <boost/hana/take_front.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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//! @cond
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template <typename Xs, typename N, typename Elements>
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constexpr auto insert_range_t::operator()(Xs&& xs, N&& n, Elements&& elements) const {
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using S = typename hana::tag_of<Xs>::type;
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using InsertRange = BOOST_HANA_DISPATCH_IF(insert_range_impl<S>,
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hana::Sequence<Xs>::value &&
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hana::Foldable<Elements>::value
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);
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#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
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static_assert(hana::Sequence<Xs>::value,
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"hana::insert_range(xs, n, elements) requires 'xs' to be a Sequence");
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static_assert(hana::Foldable<Elements>::value,
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"hana::insert_range(xs, n, elements) requires 'elements' to be a Foldable");
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#endif
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return InsertRange::apply(static_cast<Xs&&>(xs),
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static_cast<N&&>(n),
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static_cast<Elements&&>(elements));
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}
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//! @endcond
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template <typename S, bool condition>
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struct insert_range_impl<S, when<condition>> {
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template <typename Xs, typename N, typename Elements>
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static constexpr auto apply(Xs&& xs, N const& n, Elements&& e) {
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return hana::concat(
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hana::concat(
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hana::take_front(xs, n),
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hana::to<S>(static_cast<Elements&&>(e))
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),
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hana::drop_front(xs, n)
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);
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}
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};
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_INSERT_RANGE_HPP
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