Type alias for template member function

[Alvin]

Is there a way to write this more elegantly, introducing an alias for
"std::tuple_element<type_nr, tuple_t>::type"?



#include <tuple>

template<typename... types>
struct S {
using tuple_t = std::tuple<types...>;

template<size_t type_nr>
void f(typename std::tuple_element<type_nr, tuple_t>::type v1,
typename std::tuple_element<type_nr, tuple_t>::type v2,
typename std::tuple_element<type_nr, tuple_t>::type v3,
typename std::tuple_element<type_nr, tuple_t>::type v4) { }
};

[Alf P. Steinbach]

One possibility:


template< class... Types >
struct S {
template< int i >
using Arg = std::tuple_element_t<i, std::tuple<Types...>>;

template< int i >
void f( Arg<i> v1, Arg<i> v2, Arg<i> v3, Arg<i> v4 ) {}
};


Cheers & hth.,

- Alf

[Alvin]

That is better.

Thanks!