Hi!
I have a D template struct that reimplements a C++ class template
with identical memory layout for a set of types that matter to
me. Now, I want to use some C++ functions and classes that use
these template instances, from D. For that, I want to
purposefully alias the D and C++ types. However, with the C++
type being templated, I don't know how to name that type in a
extern declaration in D.
Consider, the following simplified example:
```cpp
// C++ template class (from third party library)
template<typename T, typename X>
class Foo {
// X is made part of the type as a behavior switch, but is
never instanced
T a, b;
};
using FooFloat = Foo<float>;
// own C++ function:
void bar(FooFloat f);
```
```d
// D template struct
struct Foo(T) {
T a, b;
}
alias FooFloat = Foo!float;
// How do I correctly bind the C++ function bar here?
```
Ideally, I want to pass an instance of the D implementation of
FooFloat without introducing additional wrapper functions.
I know that the whole thing does sound quite mad at first glance
and screams "bad idea!", but there is a reason why I want to try
to tread into this minefield.
