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Diffstat (limited to 'boost/hana/insert.hpp')
-rw-r--r-- | boost/hana/insert.hpp | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/boost/hana/insert.hpp b/boost/hana/insert.hpp new file mode 100644 index 0000000000..706549c5d6 --- /dev/null +++ b/boost/hana/insert.hpp @@ -0,0 +1,52 @@ +/*! +@file +Defines `boost::hana::insert`. + +@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_HPP +#define BOOST_HANA_INSERT_HPP + +#include <boost/hana/fwd/insert.hpp> + +#include <boost/hana/append.hpp> +#include <boost/hana/concat.hpp> +#include <boost/hana/concept/sequence.hpp> +#include <boost/hana/config.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 Set, typename ...Args> + constexpr decltype(auto) insert_t::operator()(Set&& set, Args&& ...args) const { + return insert_impl<typename hana::tag_of<Set>::type>::apply( + static_cast<Set&&>(set), + static_cast<Args&&>(args)... + ); + } + //! @endcond + + template <typename T, bool condition> + struct insert_impl<T, when<condition>> : default_ { + template <typename ...Args> + static constexpr auto apply(Args&& ...) = delete; + }; + + template <typename S> + struct insert_impl<S, when<Sequence<S>::value>> { + template <typename Xs, typename N, typename Element> + static constexpr auto apply(Xs&& xs, N const& n, Element&& e) { + return hana::concat(hana::append(hana::take_front(xs, n), + static_cast<Element&&>(e)), + hana::drop_front(xs, n)); + } + }; +BOOST_HANA_NAMESPACE_END + +#endif // !BOOST_HANA_INSERT_HPP |