3 Forward declares `boost::hana::symmetric_difference`.
5 @copyright Louis Dionne 2013-2017
6 Distributed under the Boost Software License, Version 1.0.
7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
10 #ifndef BOOST_HANA_FWD_SYMMETRIC_DIFFERENCE_HPP
11 #define BOOST_HANA_FWD_SYMMETRIC_DIFFERENCE_HPP
13 #include <boost/hana/config.hpp>
14 #include <boost/hana/core/when.hpp>
17 namespace boost { namespace hana {
18 // Note: This function is documented per datatype/concept only.
20 template <typename S, typename = void>
21 struct symmetric_difference_impl : symmetric_difference_impl<S, when<true>> { };
24 struct symmetric_difference_t {
25 template <typename Xs, typename Ys>
26 constexpr auto operator()(Xs&&, Ys&&) const;
29 BOOST_HANA_INLINE_VARIABLE constexpr symmetric_difference_t symmetric_difference{};
30 }} // end namespace boost::hana
32 #endif // !BOOST_HANA_FWD_SYMMETRIC_DIFFERENCE_HPP