Re: Disallowing Pre-Defined Operations

[William A Whitaker <whitaker@erols.com>]

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