From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,c5ca2cbae60e9fee
X-Google-Attributes: gid103376,public
From: Brian Rogoff <bpr@shell5.ba.best.com>
Subject: Re: OO puzzle
Date: 2000/01/02
Message-ID: <Pine.BSF.4.21.0001020832580.2498-100000@shell5.ba.best.com>#1/1
X-Deja-AN: 567440017
References: 
 <Pine.A41.3.96-heb-2.07.991222103646.28794B-100000@pluto.mscc.huji.ac.il>
 <386102F6.56CEFA22@averstar.com> <83sq9g$5ml$1@nnrp1.deja.com>
 <Pine.BSF.4.21.9912292100270.8540-100000@shell5.ba.best.com>
 <386C07D7.A24A36F5@shadow.net>
 <Pine.BSF.4.21.9912310836350.27642-100000@shell5.ba.best.com>
 <386CFDEB.946C3336@shadow.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII
X-Trace: nntp1.ba.best.com 946831200 222 bpr@206.184.139.136
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Date: 2000-01-02T00:00:00+00:00
List-Id: <comp.lang.ada>

On Fri, 31 Dec 1999, Jeffrey L Straszheim wrote:
> Brian Rogoff wrote:
> > This is really not the same, as Ada subtypes aren't like Eiffel
> > subclasses. Its more appropriate to compare Ada subtypes with
> > array bounds checking and the like.
> 
> Of course it's not the same: no two different things are ever the
> same. 

Yes, so you should compare similar features in the two languages. The 
analogous problem in Eiffel is that you don't know that you'll get a 
precondition violation at run time. Range constraints are like a
degenerate form of precondition. It isn't useful to compare them to
Eiffel's broken covariance. 

> So, here is my point: catcalls are one area where Eiffel lets
> its programmers shoot themselves in the foot. There are a few others,
> namely the subclassing rules for generics (yuck), but all in all
> I've found these problems easy to avoid, more so than avoiding,
> say, buffer problems in C. I'm just learning Ada now, so I have
> limited experience with it, but I suspect that I won't have problems
> with its "gotchas" either. At least it seems so at first glance.

Ada has its share of "gotchas", but IME most are just annoying
restrictions telling me I can't do something, rather than silently 
watching me do something stupid.

-- Brian