Re: Ada design bug or GNAT bug?

[vincent.diemunsch@gmail.com]

Le lundi 22 juin 2015 20:27:17 UTC+2, Shark8 a écrit :
> 
> Yes, anonymous accesses ARE pretty bad.
> But this does bring up the question: what missteps have been made in Ada's design?
> 

I regard the refusal to create a "class type", like Ichbiah wanted it, just like we have a protected type and a task type, as the root of evil. For the OOP concept is based on an interface that is the same and instances that are different realizations of the same concept. So we need to have two objects : 
- a class object that is an interface and manage memory (a descendant of controlled type)
- an instance object that is polymorphic.

One may think that the distinction between class type and tagged type is subtle, but the implications of it are huge : without class object one needs as replacement access to a class wide type. This has led to the use of access values everywhere when doing OOP. To ease the pain access parameters and anonymous access types were introduced...

Regards,

Vincent