"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> a �crit dans le message
news:
> Both Ada and SmallTalk [AFAIK] do not crash when such thing happens.
> But this is not the problem. The problem is that though one could wish
> to detect all such and similar cases at compile time, one cannot. This
> does not mean that we should drop compile-time checks. [To put it
> clear, Ada is right, SmallTalk is wrong! (:-))] It only means that the
> argument, "this is not allowed, because it cannot be fully checked at
> compile time" is wrong. Alas, there are many damn useful things
> uncheckable at compile time.

... with tagged types.

The benefit, and drawback, of tagged types is that they allow dynamic
typing, therefore requiring (isn't it surprising) dynamic checking. More
flexibility, less security. If you want full compile-time checking, don't
use tagged types.
At least in Ada, you have a choice!

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           J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr