Re: Ada design bug or GNAT bug?

[vincent.diemunsch@gmail.com]

Le mardi 23 juin 2015 19:15:36 UTC+2, Dmitry A. Kazakov a écrit :

> On Tue, 23 Jun 2015 09:57:43 -0700 (PDT), Vincent wrote:
> > A would rather call a set of types a category [of types], like Integers or
> > dicrete types.
> 
> Integers is a class of types, so discrete types are.

Ok ARM 2012 says :
Any set of types can be called a "category" of types, and any set of types that is closed under derivation (see 3.4) can be called a "class" of types. 

But I was trying to imagine a new category : a "class type". It would be something between :
- a general access-to-class-wide type
- a controlled object with Initialize, Adjust and Finalize.
- a protected type for the syntax of primitive operations

> >>> 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.
> >> 
> >> Why?
> > 
> > Because one need a concrete object!
> 
> tagged object is a concrete object.

Ok. I should have said, very often one need a constrained object,
and this requires an access value for polymorphic tagged objects. 

 Vincent