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- /*!
- @file
- Defines `boost::hana::union`.
- @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_UNION_HPP
- #define BOOST_HANA_UNION_HPP
- #include <boost/hana/fwd/union.hpp>
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/dispatch.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- //! @cond
- template <typename Xs, typename Ys>
- constexpr auto union_t::operator()(Xs&& xs, Ys&& ys) const {
- using S = typename hana::tag_of<Xs>::type;
- using Union = BOOST_HANA_DISPATCH_IF(union_impl<S>,
- true
- );
- return Union::apply(static_cast<Xs&&>(xs), static_cast<Ys&&>(ys));
- }
- //! @endcond
- template <typename S, bool condition>
- struct union_impl<S, when<condition>> : default_ {
- template <typename ...Args>
- static constexpr auto apply(Args&& ...) = delete;
- };
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_UNION_HPP
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