GNU bug report logs - #27177
26.0.50: Macroexpanding cl-loop and friends (make-symbol usage)

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Message #20 received at 27177 <at> debbugs.gnu.org (full text, mbox):

From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Alex <agrambot <at> gmail.com>
Cc: 27177 <at> debbugs.gnu.org
Subject: Re: bug#27177: 26.0.50: Macroexpanding cl-loop and friends
 (make-symbol usage)
Date: Thu, 01 Jun 2017 03:01:51 +0200

Alex <agrambot <at> gmail.com> writes:

> > Note that `make-symbol' doesn't return an interned symbol - what is
> > printed as "--cl-var--" above are actually different symbols.  You need
> > to enable `print-gensym' to make that visible when printing the
> > macroexpansion.  If you print with print-gensym bound to nil, you don't
> > get a correct printed representation.
>
> Enabling print-gensym in this case is even worse, since evaluating the
> macroexpanded code yields a (void-variable #:--cl-var--) error.

Oh, you need to bind `print-circle' as well, thanks npostavs.

> > So I think there is not a bug, unless your complaint is about human
> > readability or the default value of `print-gensym'.
>
> Human readability is indeed a large part of my complaint.

> Also, evaluating the macroexpanded code directly would allow for easier
> debugging, since one could make small adjustments to the output to see
> immediate results.

With print-circle and print-gensym bound, I think the result does not
really read worse than how it would look like with with `cl-gensym'
generated code.


Michael.

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