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/*!
@file
Forward declares `boost::hana::negate`.
@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_FWD_NEGATE_HPP
#define BOOST_HANA_FWD_NEGATE_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Return the inverse of an element of a group.
//! @ingroup group-Group
//!
//!
//! Example
//! -------
//! @include example/negate.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto negate = [](auto&& x) -> decltype(auto) {
return tag-dispatched;
};
#else
template <typename G, typename = void>
struct negate_impl : negate_impl<G, when<true>> { };
struct negate_t {
template <typename X>
constexpr decltype(auto) operator()(X&& x) const;
};
constexpr negate_t negate{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_NEGATE_HPP
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