Given a container of a certain type as input, is it possible to "extract" the container template and instantiate it for a different type? For example:
void f ( auto& x ) {
getContainerTemplate(x)<int> a (10); // getContainerTemplate()
// is some magic function.
}
The effect of f() should be the following depending on the type of x:
void f ( std::vector<double>& x ) {
std::vector<int> a(10);
}
or
void f ( parlay::sequence<double>& x ) { // parlay::sequence is
// another container template storing elements contiguously.
parlay::sequence<int> a(10);
}
Yes, it is possible. Using a "template template parameter" (see What are some uses of template template parameters?) instead of auto will allow f() to deduce a template type, which you can then instantiate with your own parameters, eg:
template< template<typename, typename...> class Container, typename T >
void f ( Container<T>& x ) {
Container<int> a(10);
...
}