Re: Ada Interfaces and the Liskov Substitution Principle

["Randy Brukardt" <randy@rrsoftware.com>]

"Ludovic Brenta" <ludovic@ludovic-brenta.org> wrote in message
news:871wh7i8lq.fsf@ludovic-brenta.org...
> Stefan Lucks <lucks@th.informatik.uni-mannheim.de> writes:
...
> > What do you guys think about this?
>
> I think the declaration of Stepchild.Object is illegal because ARM
> 3.9.4(12/2) states: "A type derived from a nonlimited interface shall
> be nonlimited."

Right. The most general type of interface is a limited interface; every
interface should be declared limited if possible. (We didn't make that the
default solely because it would be inconsistent with the rest of the
language.) And if it is not possible to declare the interface limited (as in
the example), then all types that include it must be nonlimited. At least
interfaces don't have the rather limiting rule that regular tagged types do,
where the limitedness can't be changed at all.

                           Randy.