Newsgroups: comp.lang.smalltalk,comp.lang.eiffel,comp.lang.ada,comp.object
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!oitnews.harvard.edu!news.cs.umb.edu!CTCnet!news.math.psu.edu!news.cse.psu.edu!rutgers!news.sgi.com!su-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!cam-news-hub1.bbnplanet.com!uunet!in1.uu.net!208.192.224.3!news.interactive.net!news
From: Richie Bielak <%nospam%richieb@calfp.com>
Subject: Re: Static vs. Dynamic typing again (was Re: OO, C++, and something much better!)
Content-Type: text/plain; charset=us-ascii
X-Nntp-Posting-User: (Unauthenticated)
Content-Transfer-Encoding: 7bit
Organization: IBS Interactive, Inc.
Message-ID: <32EE2067.4929@calfp.com>
References: <JSA.97Jan16141937@alexandria> <E44u82.6uB@syd.csa.com.au> <mheaney-ya023280001601972303180001@news.ni.net> <32DF458F.4D5C@concentric.net> <32DF94DC.6FF8@watson.ibm.com> <32DFD972.37E4@concentric.net> <32E4FC5B.242C@watson.ibm.com> <32E6862D.608B@parcplace.com> <32E764D0.23D9@calfp.com> <32E7A686.56D@parcplace.com> <32E7BD57.2558@calfp.com> <32EE045D.E39@sdrc.com>
X-Mailer: Mozilla 3.0Gold (X11; I; SunOS 5.4 sun4m)
Mime-Version: 1.0
X-Trace: 854466614/4440
X-Nntp-Posting-Host: host029.nyc.interactive.net
Date: Tue, 28 Jan 1997 15:51:03 GMT
Lines: 40
Xref: glinda.oz.cs.cmu.edu comp.lang.smalltalk:50199 comp.lang.eiffel:17834 comp.lang.ada:56670 comp.object:60439

Mark Windholtz wrote:
> 
> Richie Bielak wrote:
> >
> > but static typing _proves_ absence of certain kinds of errors.
> >
> 
> > What also wanted to say in my previous post is that static typing
> > proves that there is no call in the program that will cause
> > the "message not understood" error.
> >
> 
>   Unless you CAST anywhere in your program.
>   Then the static language version of "message not understood"
>   is either an exception or a core dump.
> 

[...]
 
>   This is my experience with C++ anyway.  Please
>   comment if casting in Eiffel provides the same
>   opportunity for run-time errors.
> 
>   The consequences of such runtime errors are
>   less severe in Smalltalk because it will not
>   core dump (mostly).
> 

Eiffel has no C-style casting. Instead Eiffel provides the "reverse
assigment 
attempt" operator to do safe "downcasting" when needed.

...richie


-- 
* richieb@netlabs.net       - at home |  Richie Bielak             *
* richieb@calfp.com         - at work |                            *
*          Home page:   http://www.netlabs.net/hp/richieb          *
*        "Fight software piracy, use free software!" (me)          *
