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Sprout/sprout/utility/pair/first.hpp
2018-12-30 17:25:21 +09:00

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/*=============================================================================
Copyright (c) 2011-2018 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_UTILITY_PAIR_FIRST_HPP
#define SPROUT_UTILITY_PAIR_FIRST_HPP
#include <sprout/config.hpp>
#include <sprout/tuple/tuple/get.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/utility/pair/tuple.hpp>
namespace sprout {
//
// first
//
template<typename T>
inline SPROUT_CONSTEXPR auto
first(T&& t)
SPROUT_NOEXCEPT_IF_EXPR(sprout::tuples::get<0>(SPROUT_FORWARD(T, t)))
-> decltype(sprout::tuples::get<0>(SPROUT_FORWARD(T, t)))
{
return sprout::tuples::get<0>(SPROUT_FORWARD(T, t));
}
} // namespace sprout
#endif // #ifndef SPROUT_UTILITY_PAIR_FIRST_HPP