Article View: comp.lang.misc
Article #3587Re: Run-time Type Errors in Smalltalk
From: Markku Sakkinen
Date: Thu, 18 Apr 1991 05:22
Date: Thu, 18 Apr 1991 05:22
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2388 bytes
In article <2023@optima.cs.arizona.edu> gudeman@cs.arizona.edu (David Gudeman) writes:
>In article <1991Apr15.234559.16293@comp.vuw.ac.nz> Brian Boutel writes:
> ...
>]The claim that testing catches all errors is laughable.
>
>Sure is. Did someone make that claim?
That is how I too have understood several of your postings.
You have even added "in a matter of minutes".
Glad to hear you don't really think so.
> ...
>]So what can be said about all the errors in the quoted C++ project that
>]were not caught by testing and are still in the production code?
>]
>]I'll tell you. They are not type errors.
>
>Nope, you can't tell that. C++ production code can core dump due to a
>type error. That's because to implement something that really needs
>dynamic typing you often have to use tricks that leave all type
>checking up to the programmer.
C and C++ are a bad choice to represent statically typed languages
in these comparisons. C descends from some truly _untyped_ languages
and that still shows. It has only partial type checking at compile
time and none whatsoever at run time. C++ is not essentially better.
>What can you say about errors that occur in production code in
>dynamically typed languages? First, they are not caused by the
>necessity of getting around the static type checker. Second, they are
>almost never type errors of the sort that could have been caught by a
>static type checker. Third, if they are type errors they cannot cause
>a core dump or other unpredictable behavior.
However, there are situations in which "Message not understood"
is not essentially better than a core dump. Typically, embedded
systems running unoperated.
Markku Sakkinen
Department of Computer Science and Information Systems
University of Jyvaskyla (a's with umlauts)
PL 35
SF-40351 Jyvaskyla (umlauts again)
Finland
SAKKINEN@FINJYU.bitnet (alternative network address)
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!news.funet.fi!jyu.fi!sakkinen From: sakkinen@jyu.fi (Markku Sakkinen) Newsgroups: comp.lang.misc Subject: Re: Run-time Type Errors in Smalltalk Message-ID: <1991Apr18.052231.25350@jyu.fi> Date: 18 Apr 91 05:22:31 GMT References: <2023@optima.cs.arizona.edu> Reply-To: sakkinen@jytko.jyu.fi (Markku Sakkinen) Organization: University of Jyvaskyla, Finland Lines: 45