RE: Dynamic typing (part 31,497)

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Article #3592

#3592

From: Nick Rothwell
Date: Wed, 17 Apr 1991 14:00

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In article <1957@optima.cs.arizona.edu>, gudeman@cs.arizona.edu (David Gudeman) writes:
> In article  <8872@skye.cs.ed.ac.uk> Nick Rothwell writes:
> ]
> ]No runtime *type* errors. Runtime errors are restricted to a small set of
> ]exception conditions defined by the language.
> 
> The only runtime error you have eliminated with static type checking
> is a "message not understood" or "domain error".  The elimination of
> this single type of error hardly seems to justify the limitations on
> expressiveness

It does if that error accounts for a huge proportion of errors.

> How
> much are you willing to give up in expressiveness to find the most
> trivial and obvious programming error a few minutes earlier?

If it were always a case of a few minutes (and if the runtime system
were as informative as the compiler when errors occured), then it wouldn't
be worth it. But, runtime type errors are indeterminate since not every
execution path is guaranteed to be followed within a fixed period of
testing time.

-- 
Nick Rothwell,	Laboratory for Foundations of Computer Science, Edinburgh.
                nick@lfcs.ed.ac.uk    <Atlantic Ocean>!mcsun!ukc!lfcs!nick
~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~
"Playing strip poker with an exhibitionist somehow defeats the object...."

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From: nick@cs.edinburgh.ac.uk (Nick Rothwell)
Newsgroups: comp.lang.misc
Subject: RE: Dynamic typing (part 31,497)
Message-ID: <9026@skye.cs.ed.ac.uk>
Date: 17 Apr 91 14:00:24 GMT
References: <1957@optima.cs.arizona.edu>
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Organization: Tasha Yar Appreciation Soc... oh, sh*t
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