GNU bug report logs - #73886
29.4; Confusing info about void function cells in Emacs Lisp manual

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Message #17 received at 73886 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Ulrich Müller <ulm <at> gentoo.org>, 73886 <at> debbugs.gnu.org
Subject: Re: bug#73886: 29.4; Confusing info about void function cells in
 Emacs Lisp manual
Date: Sat, 19 Oct 2024 22:12:48 -0400

>> Section 13.9 "Accessing Function Cell Contents" of the GNU Emacs Lisp
>> Reference Manual emphasizes the distinction between void and nil
>> in function cells:
>> 
>> |    Note that void is not the same as ‘nil’ or the symbol ‘void’.
>> | The symbols ‘nil’ and ‘void’ are Lisp objects, and can be stored into
>> | a function cell just as any other object can be (and ‘void’ can be a
>> | valid function if you define it with ‘defun’).  A void function cell
>> | contains no object whatsoever.

Oops.  Looks like I missed this part when I changed it back around
Emacs-24.4:

    ** In 'symbol-function', nil and "unbound" are indistinguishable.
    'symbol-function' does not signal a 'void-function' error any more.
    To determine if a symbol's function definition is void, use 'fboundp'.

> I think the manual is wrong.

Indeed.  It was right for Emacs<24.4, tho.


        Stefan

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