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From: Ted Dennison <dennison@telepath.com>
Subject: Re: Operators -> unit analysis
Date: 2000/01/07
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In article <853lkg$tgj$1@nnrp1.deja.com>,
  Robert Dewar <robert_dewar@my-deja.com> wrote:
> In article <3874D0BE.82F04763@Raytheon.com>,

> Algol-68 designers regard it as a horrible mistake. One should
> only rely on precedence of operators where the precedence rules
> are clear and obvious. This cannot be the case by definition
> for user defined precedences.

I think you are saying that in practice it gets to be a mess. I do
appreciate that. But the above statement would only be true if they are
truly user-defined. If the operators and precedences are in fact created
by the user to match existing precedences for established mathematical
notations, then I think it *would* be clear and obvious to any user. For
instance, if I make a notation including operators to mimic BNF
productions (which I am doing, btw), any reasonable user would expect to
*not* have to put parenthesis around a production's right side just to
keep the BNF "::=" operator from being evaluated prematurely.

--
T.E.D.


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