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From: "J-P. Rosen" <rosen@adalog.fr>
Newsgroups: comp.lang.ada
Subject: Re: Preventing type extensions
Date: Mon, 13 Sep 2010 23:13:16 +0200
Organization: Adalog
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Date: 2010-09-13T23:13:16+02:00
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Le 13/09/2010 14:55, Cyrille a �crit :
>> Some time ago on c.l.a. we had a long discussion on the goodness or
>> badness of re-dispatch, without coming to an agreement. I don't want to
>> repeat that discussion, just to point out, again, that Dmitry's opinion
>> is not universal.
> 
> Far from it indeed. In order to follow the "simple dispatch" rule as
> described in OOTiA, one need to (almost) systematically re-dispatch.
> It seems to me that the vulnerabilities associated with not following
> the simple dispatch rule are significant: it is difficult to guarantee
> the integrity of the objects that are manipulated as soon as view
> conversions are used or some primitives ops are inherited while others
> are overridden.
> I understand the arguments in the other direction (against redispatch)
> but they do not look so compelling to me, especially in a context
> where LSP is understood and verified.

These arguments make sense for languages without the notion of
class-wide types. However, I think that redispatching can be replaced
with class-wide operations, with great benefits from the POV of testing.

Cyril, will you come to the workshop? That would be very valuable.

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