Sprout/sprout/functional/pre_decrement.hpp
2019-01-07 17:47:17 +09:00

37 lines
1.1 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 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_FUNCTIONAL_PRE_DECREMENT_HPP
#define SPROUT_FUNCTIONAL_PRE_DECREMENT_HPP
#include <utility>
#include <sprout/config.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/functional/transparent.hpp>
namespace sprout {
//
// pre_decrement
//
template<typename T = void>
struct pre_decrement;
template<>
struct pre_decrement<void>
: public sprout::transparent<>
{
public:
template<typename T>
SPROUT_CONSTEXPR decltype(--std::declval<T>())
operator()(T&& x)
const SPROUT_NOEXCEPT_IF_EXPR(--std::declval<T>())
{
return --SPROUT_FORWARD(T, x);
}
};
} // namespace sprout
#endif // #ifndef SPROUT_FUNCTIONAL_PRE_DECREMENT_HPP