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From: mailman@telfon.enet.dec.com (Steven M. Mailman)
Newsgroups: comp.lang.pascal
Subject: Re: Pascal Puzzle: what is a standard compiler
Message-ID: <23941@shlump.lkg.dec.com>
Date: 28 Jun 91 14:57:30 GMT
Sender: newsdaemon@shlump.lkg.dec.com
Organization: Digital Equipment Corporation
Lines: 30


In article <2581@cybaswan.UUCP>, cslaurie@cybaswan.UUCP (Laurie Moseley ) writes...
>This puzzle seems to depend heavily upon non-standard compiler vagaries.
> 
>Firstly, I am having some difficulty in thinking up situations in
>which I would wish to write:
> 
>	for y := 1 to y do
> 
>Secondly one is also relying on the compiler to pick up the value of the loop
>termination variable (the second y) and storing it separately from
>the loop control variable (even though they should be identical - they
>have the same identifier and are within the same scope).

	It *is* depending on the compiler to pick up value and store it
	in a temporary variable.  The Pascal standard specifies that
	a compiler MUST do this (or behave asif it saved value).

	Also, it *is* undefined after the loop is done.  It may have
	the value 10 but it is still undefined, i.e. you should
	not depend on it being 10.  With some compilers the
	value may be 11.  The Pascal standard says that it is
	illegal to even look at that value.

------
Steve Mailman
Digital Equipment Corporation
mailman@tle.enet.dec.com
Disclaimer:  The opinions and statements expressed by me are not
             necessarily those of Digital Equipment Corporation.