Re: What would you like in Ada202X?

[Adam Beneschan <adam@irvine.com>]

On Wednesday, April 25, 2012 7:52:52 PM UTC-7, Randy Brukardt wrote:
> "Yannick Duchêne (Hibou57)" wrote in message 
> news:op.wdcj0snyule2fv@douda-yannick...
> ...
> >> If method resolution clause exists:
> >>
> >> type T is new I1 and I2;
> >> overriding(I1.X) procedure X1 (Obj : T);
> >> overriding(I2.X) procedure X2 (Obj : T);
> >
> >The above may still present issues with overloading. Imagine X exist with 
> >multiple signatures, for both I1 and I2: as your proposal does not refer 
> >the precise signature, this would still be ambiguous.
> 
> Right; simple names are never enough. You always need the full profile, else 
> you still have holes. Those holes were bad enough for pragmas that we dumped 
> the entire mess and invented aspect specifications for Ada 2012.
> 
> We actually considered something like this for Ada 2005, but decided it just 
> goes too far. In part, that's because having such a problem suggests bad 
> design somewhere: it should never be the case that you have two routines 
> with the same name and profile that have different meanings.

I'm not sure that's an indicator of bad design, in this case.  It seems quite plausible that the interface types, I1 and I2, were designed by people who had nothing to do with each other, working on totally different open-source projects; and it happened that they came up with the same name and profile for one of their methods.  You probably can't attribute that to bad design.  Now someone else wants to make use of reusable open-source software and they want to define a type that implements both the I1 and I2 interfaces.  I don't think it seems all that far-fetched.  I'm only a little familiar with other languages (such as D-Flat) that support interfaces, but from what little I know, it does seem like a definite problem in those languages.

                    -- Adam