Path: utzoo!attcan!uunet!wuarchive!usc!ucsd!rutgers!att!cbnewsc!lgm
From: lgm@cbnewsc.att.com (lawrence.g.mayka)
Newsgroups: comp.object
Subject: Re: Do we really need types in OOPL's?
Summary: Type errors, experiments, and eiffel
Message-ID: <1990Oct11.004854.11732@cbnewsc.att.com>
Date: 11 Oct 90 00:48:54 GMT
References: <0yw10qr@Unify.Com> <411@eiffel.UUCP> <736@tetrauk.UUCP> <18261.27131385@qut.edu.au>
Organization: AT&T Bell Laboratories
Lines: 53

In article <18261.27131385@qut.edu.au>, rnews@qut.edu.au writes:
> In article <1990Oct5.013201.12459@cbnewsc.att.com>, lgm@cbnewsc.att.com (lawrence.g.mayka) writes:
> > The occurrence of a type error, far from being a "crash and burn at
> > runtime", is merely a software exception like any other, and responds
> > to similar treatment by the appropriate exception handler.
> 
> Which in most cases of type errors will not be able to recover and
> will propagate back up to the operating system and kill your system;
> still not a terribly useful situation from the users point of view.

If a type error kills your program, either your program or your system
is in serious need of improvement.  Providing restart alternatives may
be appropriate in interactive applications; an error report and
resumption of regular processing are more sensible in an unstaffed,
continuously running application.

> > I encourage those who claim that dynamic typing is "the wrong choice"
> > for large software systems to actually run experiments on large (e.g.,
> > over a million lines of source) software systems, comparing dynamic
> > vs. static typing - above all, for ease of modification and extension.
> 
> Seeing as you are the one to do the encouraging would you care to show
> us the results of your tests?  Or are your opinions based on personal
> preference like everyone elses?

Any such results would be highly proprietary.

> Why is it that the evangelists in the dynamic typing crowd refuse to
> believe that you can combine the advantages of both static and dynamic
> typing in one language?  Look at Eiffel and Modula-3 as examples of
> languages that have made an attempt at combining the best of both worlds.
> My own language OOM2 will in its later incarnations also attempt to
> achieve a good union of static and dynamic typing (it already does some).

Sorry, for my purposes I must rule out

a) Immature languages without commercial support (presumably OOM2).

b) Languages that essentially preclude precise (i.e., not
"conservative") garbage collection (Modula-3).

Eiffel is an interesting alternative, but has yet to show sufficient
maturity (e.g., multiple competitive implementations) and breadth of
applicability (e.g., employment as the principal language of a
competitive workstation operating system).  In any case, I do not see
Eiffel as taking me far enough toward the goals of my work.


	Lawrence G. Mayka
	AT&T Bell Laboratories
	lgm@iexist.att.com

Standard disclaimer.