1 // { dg-do compile { target c++11 } } 2 // A tuple type 3 template<typename... Args> struct tuple { }; 4 5 // Determine if two types are the same 6 template<typename T, typename U> 7 struct is_same { 8 static const bool value = false; 9 }; 10 11 template<typename T> 12 struct is_same<T, T> { 13 static const bool value = true; 14 }; 15 16 // Append 'T' to the end of Tuple 17 template<typename T, typename Tuple> 18 struct append_to_tuple; 19 20 template<typename T, typename... Args> 21 struct append_to_tuple<T, tuple<Args...> > { 22 typedef tuple<Args..., T> type; 23 }; 24 25 // Reverse a sequence of arguments (and return the result as a tuple) 26 template<typename... Args> struct reverse; 27 28 template<typename T, typename... Args> 29 struct reverse<T, Args...> { 30 typedef typename append_to_tuple<T, typename reverse<Args...>::type>::type 31 type; 32 }; 33 34 template<> 35 struct reverse<> { 36 typedef tuple<> type; 37 }; 38 39 int a0[is_same<reverse<>::type, tuple<> >::value? 1 : -1]; 40 int a1[is_same<reverse<int>::type, tuple<int> >::value? 1 : -1]; 41 int a2[is_same<reverse<char, int>::type, tuple<int, char> >::value? 1 : -1]; 42 int a3[is_same<reverse<char, int, long>::type, tuple<long, int, char> >::value? 1 : -1]; 43