/*! @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