Assigning Interface to Object

Steven Schveighoffer schveiguy at
Thu Jan 20 05:01:38 PST 2011

On Thu, 20 Jan 2011 02:01:26 -0500, Mandeep Singh Brar  
<mandeep at> wrote:

> "This would be easily resolved if interfaces were known to be Objects. "
> But shouldnt this be the case, because there would be nothing called as  
> an
> Interface which can be pointed to; it would be an Object which is  
> implementing an
> interface which is being pointed to. So shouldnt Interfaces be Objects  
> too.
> Otherwise, wouldnt it defeat the purpose of having Object as the base  
> class for
> everything.

The issue is COM interfaces.  What bugs me about it is, whether an  
interface derives from IUnknown is known at compile time.  I don't think  
it's possible to define an interface that *doesn't* derive from IUnknown  
that is not a D Object.  I believe the compiler even handles IUnknown  
interfaces differently.

I think the problem is that COM support was added when compile-time  
functionality was in its infancy.  There are quite a few legacy problems  
due to that.  For instance, the builtin array sort routine does not use  
compile-time information.

It would be nice to fix this problem, but I'm not sure how willing Walter  
is to do it.  For sure, we need a solution to the opEquals problem.


More information about the Digitalmars-d-learn mailing list