I want to add a Phobos module with template mixins for common idioms.

[Jonathan M Davis]

On Saturday, May 25, 2013 00:08:37 Dmitry Olshansky wrote:
> 24-May-2013 22:13, Jonathan M Davis пишет:
> > Lacking a proper language solution, we could create something similar to
> > Rebindable but for shared.
> 
> Then in my vision built-in OOP has failed if we need at least 2 wrapper
> types implemented as structs on top of built-in refs. Then recall (to be
> implemented) RefCounted!ClassType and we have yet another library land
> solution to make OOP types with ref-counting.
> 
> On occasion I've been enumerating the amount of special casing class
> references require and truth be told I fail to see the benefit of having
> them as built-in outweigh the cost. With multiple alias this I could
> have implemented the OOP in library just fine as Ref!T struct. Then
> Ref!(const(T)) is ConstRef!T
> Ref!(shared(T)) is SharedRef!T
> 
> And now UDAs can serve for override/virtual, inheritance etc.

Overall, I think that OOP in D works fine, but we have some definite issues with 
const due to how Object is currently set up, and the fact that the type system 
can't distinguish between a reference to a class object and the class object 
itself is definitely annoying, and I have no idea why it works that way (though 
my guess would be that it's simply the side effect of making it so that they 
have to live on the heap). We would definitely be better off if we could fix 
that. I do think that the remaining issues with OOP in D are quite fixable 
though. It just takes time and effort, and doing stuff like removing 
unnecessary functions from Object are probably blocked by the AA mess. So, we 
definitely have problems, but they're not insurmountable.

On the other hand, with regards to this particular problem, as Walter inquires 
in the bug report for not being able to have local references to shared 
objects, I have no idea what the use case for such would even be.

- Jonathan M Davis