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From: jsa@alexandria (Jon S Anthony)
Subject: Re: OO, C++, and something much better!
In-Reply-To: Eric Clayberg's message of Wed, 22 Jan 1997 16:57:20 -0500
Message-ID: <JSA.97Jan24191048@alexandria>
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Organization: Organon Motives, Inc.
References: <JSA.97Jan16141937@alexandria> <5buodl$bci@boursy.news.erols.com>
	<32E2FEC7.2F7B@concentric.net> <5bvncj$gqg$1@A-abe.resnet.ucsb.edu>
	<32E47B4B.56D9@concentric.net> <6PI998tV3RB@herold.franken.de>
	<32E68D40.65EC@parcplace.com>
Date: Sat, 25 Jan 1997 00:10:48 GMT
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Xref: glinda.oz.cs.cmu.edu comp.object:60261 comp.lang.c++:242783 comp.lang.ada:56411 comp.lang.smalltalk:49901 comp.lang.eiffel:17643

In article <32E68D40.65EC@parcplace.com> Eric Clayberg <clayberg@parcplace.com> writes:

> What about if your program crashed because you tried to address a null
> pointer? Does this mean you shouldn't use C or C++?

Yes.  1/2 :-)


> Almost all "message not understood" errors are simply messages sent
> to nil (the moral equivalent of a null pointer).

This doesn't seem much better...


> This usually happens either when something isn't initialized yet or
> it has been prematurely released - certainly mot uncommon
> occurrences in the static typing world.

For non dispatched operations in a statically typed language with
strong typing, this would not happen.  For dispatched operations in
such a language, it would be an unusual circumstance.


> Real type errors (e.g., those that a static typing system would
> actually catch) rarely ever occur in Smalltalk.

Huh?  You clearly have a rather limited view of strong static typing.
What you are really saying is that weak static typing provides little
structure (your "real type error").  So what?  Static and dynamic are
orthogonal to whether the type system is highly expressive and
strongly enforced.


> The simplicity and consistency of the language drastically reduces
> the scenarios where a real type error would occur. On those rare

Baloney.


> occasions where a type error does occur, Smalltalk's excellent
> debugging facilities make them very easy to correct.

Irrelevant in a fielded piece of software.  Invoking a debugger for a
type error is not particularly useful while your assembly line grinds
to a halt or otherwise chews up prodigious resources while you call in
the developers to have a look at the "debugging screen".

 
> But rather that guess about Smalltalk, why not give a try and see for
> yourself? You can download Smalltalk Express (a fully functional 16-bit
> Windows Smalltalk IDE) for free from http://www.objectshare.com.

Hey, ST is nice - just don't make out that its dynamic typing is as
safe as a statically checked strongly typed language in high
reliability scenarios.

/Jon
-- 
Jon Anthony
Organon Motives, Inc.
Belmont, MA 02178
617.484.3383
jsa@organon.com

