/*
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@Copyright Barrett Adair 2015-2017
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_CLBL_TRTS_APPLY_RETURN_HPP
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#define BOOST_CLBL_TRTS_APPLY_RETURN_HPP
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#include <boost/callable_traits/detail/core.hpp>
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namespace boost { namespace callable_traits {
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BOOST_CLBL_TRTS_DEFINE_SFINAE_ERROR_ORIGIN(apply_return)
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BOOST_CLBL_TRTS_SFINAE_MSG(apply_return, invalid_types_for_apply_return)
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namespace detail {
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template<typename T, typename R>
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struct apply_return_helper {
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using type = typename detail::traits<T>::template apply_return<R>;
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};
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//special case
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template<typename... Args, typename R>
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struct apply_return_helper<std::tuple<Args...>, R> {
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using type = R(Args...);
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};
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}
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//[ apply_return_hpp
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/*`
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[section:ref_apply_return apply_return]
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[heading Header]
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``#include <boost/callable_traits/apply_return.hpp>``
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[heading Definition]
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*/
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template<typename T, typename R>
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using apply_return_t = //see below
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//<-
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detail::try_but_fail_if_invalid<
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typename detail::apply_return_helper<T, R>::type,
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invalid_types_for_apply_return>;
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namespace detail {
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template<typename T, typename R, typename = std::false_type>
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struct apply_return_impl {};
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template<typename T, typename R>
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struct apply_return_impl <T, R, typename std::is_same<
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apply_return_t<T, R>, detail::dummy>::type>
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{
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using type = apply_return_t<T, R>;
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};
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}
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//->
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template<typename T, typename R>
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struct apply_return : detail::apply_return_impl<T, R> {};
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//<-
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}} // namespace boost::callable_traits
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//->
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/*`
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[heading Constraints]
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* `T` must one of the following:
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* `std::tuple` template instantiation
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* function
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* function pointer
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* function reference
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* member function pointer
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* member data pointer
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* If `T` is a pointer, it may not be cv/ref qualified
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[heading Behavior]
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* When `T` is `std::tuple<Args...>`, the aliased type is `R(Args...)`.
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* When `T` is a function, function pointer, function reference, or member function pointer, the aliased type's return type is `R`, but is otherwise identical to `T`.
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* When `T` is a member data pointer of class `foo` to a `U` type (such that `T` is `U foo::*`), the aliased type is `R foo::*`.
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[heading Input/Output Examples]
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[table
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[[`T`] [`apply_return_t<T, float>`]]
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[[`std::tuple<int, int>`] [`float(int, int)`]]
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[[`int()`] [`float()`]]
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[[`int (&)()`] [`float(&)()`]]
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[[`int (*)()`] [`float(*)()`]]
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[[`int (*)(...)`] [`float(*)()`]]
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[[`int(foo::*)()`] [`float(foo::*)()`]]
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[[`int(foo::*)() &`] [`float(foo::*)() &`]]
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[[`int(foo::*)() &&`] [`float(foo::*)() &&`]]
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[[`int(foo::*)() const`] [`float(foo::*)() const`]]
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[[`int(foo::*)() transaction_safe`] [`float(foo::*)() transaction_safe`]]
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[[`int foo::*`] [`float foo::*`]]
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[[`int`] [(substitution failure)]]
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[[`int (*const)()`] [(substitution failure)]]
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]
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[heading Example Program]
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[/import ../example/apply_return.cpp]
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[apply_return]
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[endsect]
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*/
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//]
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#endif
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