GNU bug report logs - #30070
27.0.50; cl-print sometimes prints self-referencing objects as #1=#<thing>

Previous Next

Full log

Message #8 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Michael Heerdegen <michael_heerdegen <at> web.de>
Cc: bug-gnu-emacs <at> gnu.org
Subject: Re: 27.0.50;
 cl-print sometimes prints self-referencing objects as #1=#<thing>
Date: Wed, 10 Jan 2018 15:39:46 -0500

> That gives me "#1=#<thing>".  That's weird because the printed
> representation of the thing doesn't refer to itself.

Yes, it's a known misfeature (to me at least).  I don't know how we
could fix it, tho: the cycle-detection is done in a preprocessing phase
which doesn't know about any print format (nor about cl-print), so by
the time we learn the the object will be printed as "#<thing>", we have
already printed "#1=".

To fix it, I have the impression that we'd have to make cl-print a lot
more complex, and potentially its API as well (e.g. add a matching
cl-preprocess method additionally to cl-print-object).


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.