scope(~this)

[Nicholas Wilson via Digitalmars-d-learn]

On Sunday, 12 March 2017 at 21:38:44 UTC, Inquie wrote:
> Is there any easy way to create a scope for termination of the 
> object?
>
> I have a template method that takes a type and allocates and 
> deallocates based on that type.
>
> class bar
> {
>    void foo(T)()
>    {
>       T x;
>       alloc(x);
>       scope(~this) dealloc(x); // hypothetical that wraps the 
> statement in a lambda and deallocates in the destructor
>
>       ... x must stay allocated until class instance 
> termination(has to do with COM, can't release it in foo)
>    }
>
> }
>
> Now, x cannot be a field because T is unknown(i suppose I could 
> use object, void*, etc, but...).
>

If it is COM then you should use IUnknown (the COM root 
interface),or if you are expecting multiple calls to foo, an 
array of IUnknown. I think the GC will clean up completely for 
you in either case and call release(?) on the member(s).

Also as it is COM you probably don't need to template it, just 
choose T to be the most recent ancestor of all (old) T's you 
would be expecting foo to be instantiated with (e.g. IUnknown if 
you expect any COM object.