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

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From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Philipp Stephani <p.stephani2 <at> gmail.com>
Cc: 27776 <at> debbugs.gnu.org
Subject: 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.

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