C++ 0x 머지 튜플

Question

하나의 튜플에 튜플이나 타입의리스트를 병합하기위한 일반적인 템플릿이 필요합니다. 컴파일 할 때 오류가 발생합니다.

template<typename... Types> 
struct merge_tuples{ typedef std::tuple<> type;}; 

template<typename Type> 
struct merge_tuples<Type> { 
    typedef std::tuple<Type> type; 
}; 

template<typename...Types> 
struct merge_tuples<std::tuple<Types...>> { 
    typedef std::tuple<Types...> type; 
}; 

template<typename...Types1,typename...Types2> 
struct merge_tuples<std::tuple<Types1...>,std::tuple<Types2...>> { 
    typedef std::tuple<Types1...,Types2...> type; 
}; 

template<typename...Types1,typename...Types2,typename...Rest> 
struct merge_tuples<std::tuple<Types1...>,std::tuple<Types2...>,Rest...> { 
    typedef decltype(merge_tuples<std::tuple<Types1...,Types2...>,decltype(merge_tuples<Rest...>::type)>::type) type; 
}; 

template<typename...Types1,typename Type> 
struct merge_tuples<std::tuple<Types1...>,Type> { 
    typedef std::tuple<Types1...,Type> type; 
}; 
typedef std::tuple<int,double> int_double; 
typedef merge_tuples<int_double,int_double,int_double>::type megred; 

내가 점점 오전 오류가 나는 당신의 충고를 따랐다 및 몇 가지 추가 변경을 통보 하워드 Hinnant 에 대해 다음

lalr_grammar.cpp:152:97: error: unexpected type name 'type': expected expression 
    typedef decltype(merge_tuples<std::tuple<Types1...,Types2...>,decltype(merge_tuples<Rest...>::type)>::type) type; 
                           ^
lalr_grammar.cpp:420:11: note: in instantiation of template class 'merge_tuples<std::__1::tuple<int, double>, std::__1::tuple<int, double>, std::__1::tuple<int, double> >' requested here 
    typedef merge_tuples<int_double,int_double,int_double>::type megred; 

Answer 1

감사이며

template<typename... Types> 
struct merge_tuples{ 
    typedef std::tuple<Types...> type; 
}; 

template<> 
struct merge_tuples<> { 
    typedef std::tuple< > type; 
}; 

template<typename Type> 
struct merge_tuples<Type> { 
    typedef std::tuple<Type> type; 
}; 

template<typename...Types> 
struct merge_tuples<std::tuple<Types...>> { 
    typedef std::tuple<Types...> type; 
}; 

template<typename...Types1,typename...Types2> 
struct merge_tuples<std::tuple<Types1...>,std::tuple<Types2...>> { 
    typedef std::tuple<Types1...,Types2...> type; 
}; 

template<typename Type1,typename Type2> 
struct merge_tuples<Type1,Type2> { 
    typedef std::tuple<Type1,Type2> type; 
}; 

template<typename Type,typename... Types> 
struct merge_tuples<Type,std::tuple<Types...>> { 
    typedef std::tuple<Type,Types...> type; 
}; 

template<typename... Types,typename Type> 
struct merge_tuples<std::tuple<Types...>,Type> { 
    typedef std::tuple<Types...,Type> type; 
}; 

template<typename...Types,typename Type,typename... Rest> 
struct merge_tuples<std::tuple<Types...>,Type,Rest...> { 
    typedef typename merge_tuples<Rest...>::type temp; 
    typedef typename merge_tuples<std::tuple<Types...,Type>,temp>::type type; 
}; 

template<typename Type,typename... Types,typename... Rest> 
struct merge_tuples<Type,std::tuple<Types...>,Rest...> { 
    typedef typename merge_tuples<Rest...>::type temp; 
    typedef typename merge_tuples<std::tuple<Type,Types...>,temp>::type type; 
}; 

template<typename...Types1,typename... Types2,typename... Rest> 
struct merge_tuples<std::tuple<Types1...>,std::tuple<Types2...>,Rest...> { 
    typedef typename merge_tuples<Rest...>::type temp; 
    typedef typename merge_tuples<std::tuple<Types1...,Types2...>,temp>::type type; 
}; 

template<typename Type1,typename Type2,typename... Rest> 
struct merge_tuples<Type1,Type2,Rest...> { 
    typedef typename merge_tuples<Rest...>::type temp; 
    typedef typename merge_tuples<std::tuple<Type1,Type2>,temp>::type type; 
};