[libcxx] r202673 - 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.

Marshall Clow mclow.lists at gmail.com
Sun Mar 2 22:18:11 PST 2014 

Author: marshall
Date: Mon Mar  3 00:18:11 2014
New Revision: 202673

URL: http://llvm.org/viewvc/llvm-project?rev=202673&view=rev
Log:
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.

Modified:
    libcxx/trunk/include/tuple
    libcxx/trunk/include/utility
    libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
    libcxx/trunk/www/cxx1y_status.html

Modified: libcxx/trunk/include/tuple
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/tuple?rev=202673&r1=202672&r2=202673&view=diff
==============================================================================
--- libcxx/trunk/include/tuple (original)
+++ libcxx/trunk/include/tuple Mon Mar  3 00:18:11 2014
@@ -82,13 +82,15 @@ template <class T> class tuple_size; //
 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<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:
 template <intsize_t I, class... T>
     typename tuple_element<I, tuple<T...>>::type&
     get(tuple<T...>&) noexcept; // constexpr in C++14
 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
 template <intsize_t I, class... T>
     typename tuple_element<I, tuple<T...>>::type&&
@@ -152,6 +154,11 @@ public:
     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
 
 template <size_t _Ip, class _Hp, bool=is_empty<_Hp>::value

Modified: libcxx/trunk/include/utility
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/utility?rev=202673&r1=202672&r2=202673&view=diff
==============================================================================
--- libcxx/trunk/include/utility (original)
+++ libcxx/trunk/include/utility Mon Mar  3 00:18:11 2014
@@ -101,30 +101,30 @@ constexpr piecewise_construct_t piecewis
 template <class T> class tuple_size;
 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_element<0, std::pair<T1, T2> >;
-template <class T1, class T2> struct tuple_element<1, std::pair<T1, T2> >;
+template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
+template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
+template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
 
 template<size_t I, class T1, class T2>
-    typename tuple_element<I, std::pair<T1, T2> >::type&
-    get(std::pair<T1, T2>&) noexcept; // constexpr in C++14
+    typename tuple_element<I, pair<T1, T2> >::type&
+    get(pair<T1, T2>&) noexcept; // constexpr in C++14
 
 template<size_t I, class T1, class T2>
-    const typename const tuple_element<I, std::pair<T1, T2> >::type&
-    get(const std::pair<T1, T2>&) noexcept; // constexpr in C++14
+    const typename const tuple_element<I, pair<T1, T2> >::type&
+    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
 
 template<size_t I, class T1, class T2>
-    typename tuple_element<I, std::pair<T1, T2> >::type&&
-    get(std::pair<T1, T2>&&) noexcept; // constexpr in C++14
+    typename tuple_element<I, pair<T1, T2> >::type&&
+    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
 
 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>
-    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>
-    constexpr T1&& get(std::pair<T1, T2>&&) noexcept; // C++14
+    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
 
 // C++14
 

Modified: libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp?rev=202673&r1=202672&r2=202673&view=diff
==============================================================================
--- libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp (original)
+++ libcxx/trunk/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp Mon Mar  3 00:18:11 2014
@@ -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, volatile T>::type, 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()
 {
     test<std::tuple<int>, 0, int>();

Modified: libcxx/trunk/www/cxx1y_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx1y_status.html?rev=202673&r1=202672&r2=202673&view=diff
==============================================================================
--- libcxx/trunk/www/cxx1y_status.html (original)
+++ libcxx/trunk/www/cxx1y_status.html Mon Mar  3 00:18:11 2014
@@ -100,7 +100,7 @@
  	<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://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> -->
   </table>

More information about the cfe-commits mailing list