Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hplabs!hpcc05!hpsciz!hpdtczb!wallace
From: wallace@hpdtczb.HP.COM (David Wallace)
Newsgroups: comp.lang.misc
Subject: Re: Dynamic typing (part 3)
Message-ID: <1610009@hpdtczb.HP.COM>
Date: 16 Apr 91 01:09:45 GMT
References: <602@optima.cs.arizona.edu>
Organization: HP Design Tech Center - Santa Clara, CA
Lines: 23

> brian@comp.vuw.ac.nz (Brian Boutel) /  9:34 pm  Apr 10, 1991 /
> Any problem solution can be programmed in a statically typed language,
> if the programmer is prepared to *design* the program before writing it.
> I would be far more confident trusting my life/safety/money to such a
> program than to some piece of hackery written in a language where
> "expressive power" is more important than solid engineering principle.

I have heard there's a quote attributed to von Neumann to the effect that any
competent programmer shouldn't need to use floating point - if you understand
the problem well enough and *design* the program appropriately, you should be
able to use appropriately scaled fixed point values throughout.  (Someone
with a better set of references than I might be able to trace the original
quote.  I've just heard it as oral folklore.)

Anyway, programmers (and users) find floating point rather useful.  Think of it
as "dynamic scaling" vs. "static scaling."  It may not be a perfect analogy,
but it's worth thinking about.  Sometimes not having to anticipate every detail
up front can give you significantly more flexibility.  (But if it's a
life-critical application, I would still like the floating-point algorithms
designed and/or checked by a competent numerical analyst.  There are
reliability issues associated with floating-point, too.)

Dave W.		(david_wallace@hpdtl.ctgsc.hp.com)