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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: In precision typing we trust
Date: Tue, 19 Aug 2025 09:29:25 +0200
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On 2025-08-19 08:24, J-P. Rosen wrote:
> Le 18/08/2025 à 17:03, Dmitry A. Kazakov a écrit :
>  >> Ada is a strongly typed language so Ada is not an OOP language.
>  >
>  > Ada is a strongly typed OO language.
> 
> More precisely:
> OOP implies a weakening of the typing system, since a wider class can 
> contain any object of the subclass.
> But in Ada, this can happen only for objects of a class-wide type; so 
> you get it only if you ask for it, and you immediately know from the 
> type of an object which values it can hold.

Yes, however class-wide objects only behave as if they held specific 
type objects. The class-wide type is still a different type, so the type 
system remains strong.

Constrained subtypes are even "weaker" in that respect, e.g. Positive 
vs. Integer.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de