Interface vs pure abstract class - speed.

[Diggory]

On Sunday, 12 May 2013 at 17:31:22 UTC, SundayMorningRunner wrote:
> Hello, let's say I have the choice between using an abstract 
> class or an interface to declare a "plan", a "template" for the 
> descendants.
>
> From the dmd compiler point of view, should I use the abstract 
> class version (so I guess that for each method call, there will 
> be a few MOV, in order to extract the relative address from the 
> vmt before a CALL) or the interface version (are the CALL 
> directly performed in this case). Are interface faster ? (to 
> get the address used by the CALL).
>
> Thx.

I would expect abstract classes to be slightly faster (certainly 
they shouldn't be slower), but the difference to be insignificant 
compared to other factors.

Deriving from an abstract base class is a much stronger 
relationship than implementing an interface, so it depends on 
your situation. If your class is a "provider" (eg. it provides 
some functionality such as being able to receive some event) then 
an interface makes more sense. If your class is a type of 
something (eg. a button is a type of gui control) then 
inheritance makes more sense.