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From: firth@sei.cmu.edu (Robert Firth)
Newsgroups: comp.lang.modula2
Subject: Re: type of limit expressions of FOR loops
Message-ID: <5013@aw.sei.cmu.edu>
Date: 12 Apr 88 13:56:07 GMT
References: <INFO-M2%88041210091555@DB0TUI11>
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Reply-To: firth@bd.sei.cmu.edu.UUCP (Robert Firth)
Organization: Carnegie-Mellon University, SEI, Pgh, Pa
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Just to add a random comment here:  wouldn't it be a good
idea to change Modula-2 so that the control variable is
LOCAL to the FOR-statement, as it is in Algol-68, BCPL, and
Ada.

First, that would get rid of the pathologies about compatibility
of the start, stop and step expressions - you could just say
that the variable is of a host type with enough range to encompass
the entire iteration range.

Secondly, it would remove about 12 PAGES of VDM in the draft
standard, that try (almost successfully) to define what it
means to "threaten" the control variable.  A major simplification,
I believe.