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From: sfk@otter.hpl.hp.com (Steve Knight)
Newsgroups: comp.lang.misc
Subject: Re: Re: Run-time Type Errors in Smalltalk (was Re: blip (was...))
Message-ID: <2400043@otter.hpl.hp.com>
Date: 17 Apr 91 12:05:52 GMT
References: <887@puck.mrcu>
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Lines: 26

Drew writes:
> The only experience with dynamically-typed systems I have are Lisp-based
> systems, just today I crashed one with a type error.  

If your system crashed, it has a serious bug.  Type errors should be caught at
run-time and put you into a debugging loop.

[Drew also suggests ML as being a serious strongly typed system.]
I had a similar type problem with ML, too.   I found a hole in the type checker
of my implementation & took a long time finding it.  It was a serious bug in
the implementation -- but not the language.  Similarly, your LISP bug
is a bug in the implementation.

Furthermore, there's not much point in taking C to task for having (void *),
when mostly every implementation of ML has the equivalent of New Jersey's
    System.Unsafe.cast : 'a -> 'b
I only say "mostly" because I don't know about POLY/ML.  (But I'll take a bet.)
This little charmer is even worse than (void *).

Admittedly, it isn't part of the language -- which is almost worse.  If some
one uses it, then the code has to be changed before it can be ported.  I 
don't like the idea of changing code that has been written using this
monstrosity.  If I am going to use packages that require it, then I will
trust the implementor to get it right once.

Steve