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/*!
@file
Defines `boost::hana::insert_range`.
@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_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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