A renewed call for interface methods with bodies

[Burton Radons]

BCS Wrote:

> Burton Radons wrote:
> [...]
> 
> 
> something just occurred to me:
> 
> The only actions that a function body in an interfaces could do to 
> "this" is function calls that would have to be virtual (or how could it 
> ever do anything) however the code generated for a interface method 
> needs to know the type of the object to be able to make the calls 
> correctly. The only reasonable way I can see to let interface functions 
> have bodies would be to in effect use a mixin.
> 
> Can anyone think of a better solution?

There aren't any problems in compiling interface methods with bodies - it's exactly the same as a class with abstract methods. This part of the compiler should behave the same between interfaces and classes, it's just prevented from doing so by the compiler's semantic checker.

This has never been a compiler issue (IIRC there were DMD versions which accidentally allowed interface methods with bodies), it's purely a language design mistake by Walter. I've been doing a LOT of COM interfacing the last half year and it's been painful every step of the way just because of this one little bit of missing polish.