GNU bug report logs - #27776
26.0.50; `print-gensym' doesn't work as advertised

Previous Next

Full log

Message #11 received at 27776 <at> debbugs.gnu.org (full text, mbox):

From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Philipp Stephani <p.stephani2 <at> gmail.com>
Cc: 27776 <at> debbugs.gnu.org
Subject: Re: bug#27776: 26.0.50; `print-gensym' doesn't work as advertised
Date: Fri, 21 Jul 2017 03:17:50 +0200

Philipp Stephani <p.stephani2 <at> gmail.com> writes:

>  The docstring of `print-gensym' says:
>
>     When the uninterned symbol appears within a recursive data structure,
>     and the symbol appears more than once, in addition use the #N# and #N=
>     constructs as needed, so that multiple references to the same symbol are
>     shared once again when the text is read back.
>
> OK, so you could read this as "the numbering is only used for
> recursive data structures". But I don't understand why; it seems
> equally appropriate for non-recursive data structures.

AFAICT...I think the docstring of `print-gensym' just fails to say that
you get that behavior only with print-circle bound non-nil.

The second problem is that docs speak about recursive data structures
when they mean data structures with shared parts.  `print-circle' is not
(only) about recursive (cyclic) structures.

In your example, it doesn't make a difference whether the list is
actually really recursive or not, as long as the same uninterned symbol
appears more than once in it.


Michael.

Previous Next

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