Specifying C++ symbols in C++ namespaces

[Kagamin]

On Wednesday, 2 April 2014 at 22:06:53 UTC, Walter Bright wrote:
> Here's Andrei's proposal:
>
>     extern (C++) template nspace() {
>         int foo();
>     }

@namespace("nspace")
extern (C++) {
   int foo();
}

> One downside of this proposal is that if we ever (perish the 
> thought!) attempted to interface to C++ templates, this design 
> would preclude that.

If we have partial C++ bindings, why not have partial template 
bindings with a subset of features already existing in D? With 
that you would only need to implement mangling and linking. An 
interesting and simple enough use case is casting:

extern(C++) T my_cast(T,U)(U);
extern(C++) interface A{}
extern(C++) interface B:A{}

A a;
B b = my_cast!B(a);