GNU bug report logs - #57397
29.0.50; cl-letf blindly macroexpands places

Previous Next

Full log

View this message in rfc822 format

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Michael Heerdegen <michael_heerdegen <at> web.de>
Cc: 57397 <at> debbugs.gnu.org, Lars Ingebrigtsen <larsi <at> gnus.org>
Subject: bug#57397: cl-letf blindly macroexpands places
Date: Thu, 25 Aug 2022 15:33:45 -0400

> to support symbol macros better:
>
> #+begin_src emacs-lisp
> (defun cl--letf (bindings simplebinds binds body)
>   ;; It's not quite clear what the semantics of cl-letf should be...10..
>   (if (null bindings)
>       (if (and (null binds) (null simplebinds)) (macroexp-progn body)..20..)
>     (let* ((binding (car bindings))
>            (place (macroexpand (car binding) macroexpand-all-environment)));<--!!
>       (gv-letplace (getter setter) place..12..))))
> #+end_src
>
> I think this is an error in the general case.  It's at least always
> wrong when (car PLACE) is a macro name with a gv spec defined.

Indeed, defining a gv spec for a macro is fiddly.

> Maybe it's enough to expand only symbol macros?

Yes, that should still cover the original need in bug#26073 without
breaking your use case.

But regardless of this, we should probably turn `gv-synthetic-place`
into a function so it's more robust.


        Stefan

Previous Next

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