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Implement LWG Paper n3887: Consistent Metafunction Aliases. This adds std::tuple_element_t<> as an alias for tuple_element<>::type. Clean up the synopsis for tuple_element in <utility> as well.

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@202673 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow
2014-03-03 06:18:11 +00:00
parent 3fef95b10d
commit 50fe0c7d61
4 changed files with 28 additions and 14 deletions
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9
include/tuple
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@@ -82,13 +82,15 @@ template <class T> class tuple_size; // undefined
template <class... T> class tuple_size<tuple<T...>>; template <class... T> class tuple_size<tuple<T...>>;
template <intsize_t I, class T> class tuple_element; // undefined template <intsize_t I, class T> class tuple_element; // undefined
template <intsize_t I, class... T> class tuple_element<I, tuple<T...>>; template <intsize_t I, class... T> class tuple_element<I, tuple<T...>>;
template <size_t _Ip, class ..._Tp>
using tuple_element_t = typename tuple_element <_Ip, _Tp...>::type; // C++14
// 20.4.1.5, element access: // 20.4.1.5, element access:
template <intsize_t I, class... T> template <intsize_t I, class... T>
typename tuple_element<I, tuple<T...>>::type& typename tuple_element<I, tuple<T...>>::type&
get(tuple<T...>&) noexcept; // constexpr in C++14 get(tuple<T...>&) noexcept; // constexpr in C++14
template <intsize_t I, class... T> template <intsize_t I, class... T>
typename tuple_element<I, tuple<T...>>::type const& typename const tuple_element<I, tuple<T...>>::type &
get(const tuple<T...>&) noexcept; // constexpr in C++14 get(const tuple<T...>&) noexcept; // constexpr in C++14
template <intsize_t I, class... T> template <intsize_t I, class... T>
typename tuple_element<I, tuple<T...>>::type&& typename tuple_element<I, tuple<T...>>::type&&
@@ -152,6 +154,11 @@ public:
typedef typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type; typedef typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type;
}; };
#if _LIBCPP_STD_VER > 11
template <size_t _Ip, class ..._Tp>
using tuple_element_t = typename tuple_element <_Ip, _Tp...>::type;
#endif
// __tuple_leaf // __tuple_leaf
template <size_t _Ip, class _Hp, bool=is_empty<_Hp>::value template <size_t _Ip, class _Hp, bool=is_empty<_Hp>::value

24
include/utility
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@@ -101,30 +101,30 @@ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
template <class T> class tuple_size; template <class T> class tuple_size;
template <size_t I, class T> class tuple_element; template <size_t I, class T> class tuple_element;
template <class T1, class T2> struct tuple_size<std::pair<T1, T2> >; template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
template <class T1, class T2> struct tuple_element<0, std::pair<T1, T2> >; template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
template <class T1, class T2> struct tuple_element<1, std::pair<T1, T2> >; template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
template<size_t I, class T1, class T2> template<size_t I, class T1, class T2>
typename tuple_element<I, std::pair<T1, T2> >::type& typename tuple_element<I, pair<T1, T2> >::type&
get(std::pair<T1, T2>&) noexcept; // constexpr in C++14 get(pair<T1, T2>&) noexcept; // constexpr in C++14
template<size_t I, class T1, class T2> template<size_t I, class T1, class T2>
const typename const tuple_element<I, std::pair<T1, T2> >::type& const typename const tuple_element<I, pair<T1, T2> >::type&
get(const std::pair<T1, T2>&) noexcept; // constexpr in C++14 get(const pair<T1, T2>&) noexcept; // constexpr in C++14
template<size_t I, class T1, class T2> template<size_t I, class T1, class T2>
typename tuple_element<I, std::pair<T1, T2> >::type&& typename tuple_element<I, pair<T1, T2> >::type&&
get(std::pair<T1, T2>&&) noexcept; // constexpr in C++14 get(pair<T1, T2>&&) noexcept; // constexpr in C++14
template<class T1, class T2> template<class T1, class T2>
constexpr T1& get(std::pair<T1, T2>&) noexcept; // C++14 constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
template<size_t I, class T1, class T2> template<size_t I, class T1, class T2>
constexpr T1 const& get(std::pair<T1, T2> const &) noexcept; // C++14 constexpr T1 const& get(pair<T1, T2> const &) noexcept; // C++14
template<size_t I, class T1, class T2> template<size_t I, class T1, class T2>
constexpr T1&& get(std::pair<T1, T2>&&) noexcept; // C++14 constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
// C++14 // C++14

7
test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
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@@ -28,7 +28,14 @@ void test()
static_assert((std::is_same<typename std::tuple_element<N, const T>::type, const U>::value), ""); static_assert((std::is_same<typename std::tuple_element<N, const T>::type, const U>::value), "");
static_assert((std::is_same<typename std::tuple_element<N, volatile T>::type, volatile U>::value), ""); static_assert((std::is_same<typename std::tuple_element<N, volatile T>::type, volatile U>::value), "");
static_assert((std::is_same<typename std::tuple_element<N, const volatile T>::type, const volatile U>::value), ""); static_assert((std::is_same<typename std::tuple_element<N, const volatile T>::type, const volatile U>::value), "");
#if _LIBCPP_STD_VER > 11
static_assert((std::is_same<typename std::tuple_element_t<N, T>, U>::value), "");
static_assert((std::is_same<typename std::tuple_element_t<N, const T>, const U>::value), "");
static_assert((std::is_same<typename std::tuple_element_t<N, volatile T>, volatile U>::value), "");
static_assert((std::is_same<typename std::tuple_element_t<N, const volatile T>, const volatile U>::value), "");
#endif
} }
int main() int main()
{ {
test<std::tuple<int>, 0, int>(); test<std::tuple<int>, 0, int>();

2
www/cxx1y_status.html
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@@ -100,7 +100,7 @@
<tr><td></td><td></td><td></td><td></td><td></td><td></td></tr> <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
<tr><td><a href="http://wiki.edg.com/twiki/pub/Wg21issaquah/FormalMotions/N3924_rand-note-v2.pdf">3924</a></td><td>LWG</td><td>Discouraging rand() in C++14</td><td>Issaquah</td><td></td><td></td></tr> <tr><td><a href="http://wiki.edg.com/twiki/pub/Wg21issaquah/FormalMotions/N3924_rand-note-v2.pdf">3924</a></td><td>LWG</td><td>Discouraging rand() in C++14</td><td>Issaquah</td><td></td><td></td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3887">3887</a></td><td>LWG</td><td>Consistent Metafunction Aliases</td><td>Issaquah</td><td></td><td></td></tr> <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3887">3887</a></td><td>LWG</td><td>Consistent Metafunction Aliases</td><td>Issaquah</td><td></td><td>Complete</td></tr>
<!-- <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr> --> <!-- <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr> -->
</table> </table>