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