/*!

@file

Defines `boost::hana::fuse`.

@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_FUSE_HPP

#define BOOST_HANA_FUSE_HPP

#include <boost/hana/fwd/fuse.hpp>

#include <boost/hana/config.hpp>

#include <boost/hana/detail/decay.hpp>

#include <boost/hana/unpack.hpp>

BOOST_HANA_NAMESPACE_BEGIN

    namespace detail {

        template <typename F>

        struct fused {

            F f;

            template <typename Xs>

            constexpr decltype(auto) operator()(Xs&& xs) const&

            { return hana::unpack(static_cast<Xs&&>(xs), f); }

            template <typename Xs>

            constexpr decltype(auto) operator()(Xs&& xs) &

            { return hana::unpack(static_cast<Xs&&>(xs), f); }

            template <typename Xs>

            constexpr decltype(auto) operator()(Xs&& xs) &&

            { return hana::unpack(static_cast<Xs&&>(xs), static_cast<F&&>(f)); }

        };

    }

    //! @cond

    template <typename F>

    constexpr auto fuse_t::operator()(F&& f) const {

        return detail::fused<typename detail::decay<F>::type>{static_cast<F&&>(f)};

    }

    //! @endcond

BOOST_HANA_NAMESPACE_END

#endif // !BOOST_HANA_FUSE_HPP