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Sprout/sprout/weed/attr_cnv/results/negate.hpp
2017-07-29 14:20:01 +09:00

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/*=============================================================================
Copyright (c) 2011-2017 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_WEED_ATTR_CNV_RESULTS_NEGATE_HPP
#define SPROUT_WEED_ATTR_CNV_RESULTS_NEGATE_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/type_traits/identity.hpp>
#include <sprout/weed/unused.hpp>
#include <sprout/weed/traits/type/is_unused.hpp>
namespace sprout {
namespace weed {
namespace attr_cnv {
namespace results {
//
// negate
//
template<typename T, typename = void>
struct negate;
// -unused -> unused
template<typename T>
struct negate<
T,
typename std::enable_if<
sprout::weed::traits::is_unused<T>::value
>::type
>
: public sprout::identity<sprout::weed::unused>
{};
} // namespace results
} // namespace attr_cnv
} // namespace weed
} // namespace sprout
#endif // #ifndef SPROUT_WEED_ATTR_CNV_RESULTS_NEGATE_HPP