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From: William A Whitaker <whitaker@erols.com>
Subject: Re: Disallowing Pre-Defined Operations
Date: 2000/03/17
Message-ID: <38D2E598.262D1CD5@erols.com>#1/1
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NNTP-Posting-Date: 18 Mar 2000 02:10:57 GMT
Newsgroups: comp.lang.ada
Date: 2000-03-18T02:10:57+00:00
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I have not been following this thread carefylly.  I had no idea it would
go on so long.  But I would like to toss in a study I did ten years ago
along this line for the units problem.  This is at 

http://www.erols.com/whitaker/metric.sty

A lot of the intermediate code is left out, only a "final" version
given, but discussion is extensive.

The study was a failure in the sense that the answer was that while one
could do such things (including forbidding unwanted operations) it was
completely impractical in a standards situation where one expects lots
of unknowable combinations.  If the problem was just three units and
seven operations, then one could afford this nonsense.

I believe that discriminants are teh only practical way to get close to
the desired result, and I will try to post a paper on that soon.

Of course, the ideal is an Ada recognition of the Units requirement and
implementation at the standard/compiler level.


Whitaker