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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: and then... (a curiosity)
Date: Fri, 5 Sep 2008 01:38:23 -0700 (PDT)
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Date: 2008-09-05T01:38:23-07:00
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Stefan Lucks wrote:
> On Thu, 4 Sep 2008,  wrote:
>
> > And again, you propose a contextual interpretation of "Y/X<100" (for X=0).
> > That is totally beyond what program analysis can achieve.
>
> No, I am not. I claim that the shortcut "and" (which in Ada unfurtunately
> is written as "and then") is the more natural and human-readable
> interpretation of "and" expressions.

Maybe my college years are too far behind but I differ here. When I
see "and", I intuitively think of a _symmetric_ operator with the same
meaning for Booleans as for arrays of Booleans and modular types (i.e.
bitwise, mathematical, pure Boolean-logic "and"). When I see "and
then", I intuitively think of an _asymmetric_ operator which only
evaluates the right hand side if the left-hand side is True.

--
Ludovic Brenta.