c++ - How to switch to typedef from template aliasing? -


i have template class implements registry design pattern. values registered keys , stored in container:

template <typename key, typename value,      template <typename...> class container > class registry { public:     typedef key   key_type;     typedef value value_type;       typedef std::pair<key_type, value_type> element_type;     typedef container<element_type> container_type;

then, can use sequence containers this:

registry<const char*,void*, std::list> r1; registry<const char*,void*, std::vector> r2;

i can use alias:

template <typename t> using alias_container = std::array<t, 10>;  registry<const char*,void*, alias_container > r4;

but can't figure out how use typedef this:

template <typename t> class my_container2  {     typedef std::array<t,3> type; };

i want this:

registry<const char*,void*, my_container2::type > r5;

thanks lot help.

type dependent on template type provided my_container2. in order use need specify template parameter like

registry<const char*,void*, my_container2<some_type>::type > r4;                                           ^^^^^^^^^ template type here

this same concept iterators standard types. can't use container_type::iterator. have use container_type<some_type>::iterator.


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