Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uwmcsd1!ig!agate!ucbvax!decwrl!sun!imagen!geof
From: geof@imagen.UUCP (Geoffrey Cooper)
Newsgroups: comp.lang.postscript
Subject: Re: Restoring elements of strings
Summary: "Bug" maintained under UltraScript
Message-ID: <1762@imagen.UUCP>
Date: 1 Aug 88 16:56:40 GMT
References: <570@etive.ed.ac.uk>
Organization: IMAGEN Corporation, Santa Clara, CA 95052-8101
Lines: 18

In article <570@etive.ed.ac.uk>, jcb@lfcs.ed.ac.uk (Julian Bradfield) writes:
> The current Postscript design does not undo changes made to elements
> of strings when it `restore's VM. Despite the warning in the Red Book,
> I know programs that use this. Question: do non-Adobe emulations of
> Postscript also emulate this bug/feature, or do they correct it?

You've answered the question.  Since there are programs that use the
"feature", the clone's will have to support it.  Of course, I can only
vouch for UltraScript.  It falls out as an obvious efficiency hack in
the way you implement PostScript save/restore.

In the presence of multitasking (e.g., News and display postscript)
which use a different implementation of save/restore, I wouldn't be
suprised to see that feature go away.

- Geof
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{decwrl,sun,saber}!imagen!geof