GNU bug report logs - #23105
25.0.92; map-put does not change its argument MAP

Previous Next

Full log

Message #27 received at 23105 <at> debbugs.gnu.org (full text, mbox):

From: Nicolas Petton <nicolas <at> petton.fr>
To: Sho Takemori <stakemorii <at> gmail.com>, 23105 <at> debbugs.gnu.org
Subject: Re: bug#23105: 25.0.92; map-put does not change its argument MAP
Date: Fri, 25 Mar 2016 16:14:43 +0100

[Message part 1 (text/plain, inline)]

Sho Takemori <stakemorii <at> gmail.com> writes:

> Thanks for the fix. But after the fix, if MAP is a list literal, then it
> raises an error.
> For example, this raises an error.
> (map-put '((a . 1)) 'a "value")
>
> This works.
> (map-put [0 1 2] 1 "value")
>
> It is an expected error?

Yes, in the sense that the same error will be raised if you try to do it
with a setf on an alist:

(setf (alist-get 'b '((a . 1))) 3) ;; => invalid-function (a . 1)

(let ((alist '((a . 1))))
  (setf (alist-get 'b alist) 3)) ;; => works fine

Note however that mutating literal lists is in general not a good idea,
as conses might be shared.

Nico

[signature.asc (application/pgp-signature, inline)]

Previous Next

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