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- /*=============================================================================
- Copyright (c) 2015 Paul Fultz II
- result_of.h
- 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 BOOST_HOF_GUARD_DETAIL_RESULT_OF_H
- #define BOOST_HOF_GUARD_DETAIL_RESULT_OF_H
- #include <boost/hof/returns.hpp>
- #include <boost/hof/config.hpp>
- #if BOOST_HOF_HAS_MANUAL_DEDUCTION || BOOST_HOF_NO_EXPRESSION_SFINAE
- #include <boost/hof/detail/and.hpp>
- #include <boost/hof/detail/holder.hpp>
- #include <boost/hof/detail/can_be_called.hpp>
- namespace boost { namespace hof { namespace detail {
- template<class F, class Args, class=void>
- struct result_of_impl {};
- template<class F, class... Ts>
- struct result_of_impl<
- F,
- holder<Ts...>,
- typename std::enable_if<can_be_called<F, typename Ts::type...>::value>::type
- >
- {
- typedef decltype(std::declval<F>()(std::declval<typename Ts::type>()...)) type;
- };
- }
- template<class T>
- struct id_
- {
- typedef T type;
- };
- template<class F, class... Ts>
- struct result_of
- : detail::result_of_impl<F, detail::holder<Ts...>>
- {};
- // template<class F, class... Ts>
- // using result_of = detail::result_of_impl<F, detail::holder<Ts...>>;
- // using result_of = id_<decltype(std::declval<F>()(std::declval<typename Ts::type>()...))>;
- }} // namespace boost::hof
- #endif
- #if BOOST_HOF_NO_EXPRESSION_SFINAE
- #define BOOST_HOF_SFINAE_RESULT(...) typename boost::hof::result_of<__VA_ARGS__>::type
- #define BOOST_HOF_SFINAE_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { return __VA_ARGS__; }
- #else
- #define BOOST_HOF_SFINAE_RESULT(...) auto
- #define BOOST_HOF_SFINAE_RETURNS BOOST_HOF_RETURNS
- #endif
- #if BOOST_HOF_HAS_MANUAL_DEDUCTION
- #define BOOST_HOF_SFINAE_MANUAL_RESULT(...) typename boost::hof::result_of<__VA_ARGS__>::type
- #if BOOST_HOF_HAS_COMPLETE_DECLTYPE && BOOST_HOF_HAS_MANGLE_OVERLOAD
- #define BOOST_HOF_SFINAE_MANUAL_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { return (__VA_ARGS__); }
- #else
- #define BOOST_HOF_SFINAE_MANUAL_RETURNS(...) BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(__VA_ARGS__) { BOOST_HOF_RETURNS_RETURN(__VA_ARGS__); }
- #endif
- #else
- #define BOOST_HOF_SFINAE_MANUAL_RESULT BOOST_HOF_SFINAE_RESULT
- #define BOOST_HOF_SFINAE_MANUAL_RETURNS BOOST_HOF_SFINAE_RETURNS
- #endif
- #endif
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