/*=============================================================================
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Copyright (c) 2015 Paul Fultz II
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result_of.h
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_HOF_GUARD_DETAIL_RESULT_OF_H
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#define BOOST_HOF_GUARD_DETAIL_RESULT_OF_H
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#include <boost/hof/returns.hpp>
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#include <boost/hof/config.hpp>
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#if BOOST_HOF_HAS_MANUAL_DEDUCTION || BOOST_HOF_NO_EXPRESSION_SFINAE
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#include <boost/hof/detail/and.hpp>
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#include <boost/hof/detail/holder.hpp>
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#include <boost/hof/detail/can_be_called.hpp>
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namespace boost { namespace hof { namespace detail {
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template<class F, class Args, class=void>
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struct result_of_impl {};
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template<class F, class... Ts>
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struct result_of_impl<
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F,
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holder<Ts...>,
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typename std::enable_if<can_be_called<F, typename Ts::type...>::value>::type
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>
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{
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typedef decltype(std::declval<F>()(std::declval<typename Ts::type>()...)) type;
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};
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}
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template<class T>
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struct id_
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{
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typedef T type;
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};
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template<class F, class... Ts>
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struct result_of
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: detail::result_of_impl<F, detail::holder<Ts...>>
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{};
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// template<class F, class... Ts>
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// using result_of = detail::result_of_impl<F, detail::holder<Ts...>>;
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// using result_of = id_<decltype(std::declval<F>()(std::declval<typename Ts::type>()...))>;
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}} // namespace boost::hof
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#endif
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#if BOOST_HOF_NO_EXPRESSION_SFINAE
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#define BOOST_HOF_SFINAE_RESULT(...) typename boost::hof::result_of<__VA_ARGS__>::type
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#define BOOST_HOF_SFINAE_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { return __VA_ARGS__; }
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#else
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#define BOOST_HOF_SFINAE_RESULT(...) auto
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#define BOOST_HOF_SFINAE_RETURNS BOOST_HOF_RETURNS
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#endif
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#if BOOST_HOF_HAS_MANUAL_DEDUCTION
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#define BOOST_HOF_SFINAE_MANUAL_RESULT(...) typename boost::hof::result_of<__VA_ARGS__>::type
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#if BOOST_HOF_HAS_COMPLETE_DECLTYPE && BOOST_HOF_HAS_MANGLE_OVERLOAD
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#define BOOST_HOF_SFINAE_MANUAL_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { return (__VA_ARGS__); }
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#else
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#define BOOST_HOF_SFINAE_MANUAL_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { BOOST_HOF_RETURNS_RETURN(__VA_ARGS__); }
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#endif
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#else
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#define BOOST_HOF_SFINAE_MANUAL_RESULT BOOST_HOF_SFINAE_RESULT
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#define BOOST_HOF_SFINAE_MANUAL_RETURNS BOOST_HOF_SFINAE_RETURNS
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#endif
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#endif
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