Is it time to deprecate COM compatibility through D interfaces?

[Jason House]

Steven Schveighoffer Wrote:

> Given that structs have become extremely powerful, and with the advent of  
> opDispatch, would it be possible to deprecate supporting COM via D  
> interfaces in favor of a library solution?

Don suggested defining them the same way as C++ classes.


> 
> There are some crappy drawbacks for having interface be dual-purposed:
> 
> - Although 99.9% of interfaces are actually instances of Object, you can't  
> call Object functions directly on an interface.  This includes opEquals,  
> opCmp, toString and friends.
> - They are not implicitly castable to Object.
> - There is no centralized base interface, so there is no argument type you  
> can use that can accept any interface.  For instance, if you wanted to do  
> some runtime reflection to determine an interface's methods or something.
> - All these drawbacks are absolutely pointless on non-Microsoft OSes.

Casting interfaces is frequently an expensive runtime operation. It's the price that we pay for allowing more than single inheritance with interfaces. I don't like the idea of implicitly doing expensive operations.