From: Drew Adams <drew.adams@oracle.com>
To: Heime <heimeborgia@protonmail.com>,
Heime via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org>
Subject: RE: [External] : Handling nil values in optional argument
Date: Fri, 12 Jul 2024 02:37:12 +0000 [thread overview]
Message-ID: <SJ0PR10MB54880EEF189CA06CDDED043BF3A62@SJ0PR10MB5488.namprd10.prod.outlook.com> (raw)
In-Reply-To: <q8ObD2xSp-y71FsJI3txjwqQMgV4FX4yyCSiagy0zOSkw-K2od7dpmmVRwJjkrxmvDBBKBdbikv8QNTJB4dJY0Q3lsHqinI3gWB3aI1yo5U=@protonmail.com>
> I have the following tool, but I want that if I pass nil in the third
> argument,
> the function does not assume that fyr was not supplied, but that fyr is
> actually
> to be used as a nil value.
>
> (defun mundu (monbf funcs labels &optional fyr)
> (unless fyr (setq fyr t))
You can't. nil is the default value for an optional argument.
Instead, your code can use something other than nil for the value that you pass as an explicit argument. It can use the singleton list (nil), for example.
next prev parent reply other threads:[~2024-07-12 2:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-11 22:38 Handling nil values in optional argument Heime
2024-07-12 2:37 ` Drew Adams [this message]
2024-07-12 4:37 ` [External] : " Michael Heerdegen via Users list for the GNU Emacs text editor
2024-07-12 12:48 ` Heime
2024-07-13 4:56 ` Michael Heerdegen via Users list for the GNU Emacs text editor
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=SJ0PR10MB54880EEF189CA06CDDED043BF3A62@SJ0PR10MB5488.namprd10.prod.outlook.com \
--to=drew.adams@oracle.com \
--cc=heimeborgia@protonmail.com \
--cc=help-gnu-emacs@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.