all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
From: Emanuel Berg <incal@dataswamp.org>
To: help-gnu-emacs@gnu.org
Subject: Re: Executing function only if another function is defined
Date: Mon, 25 Jul 2022 03:39:25 +0200	[thread overview]
Message-ID: <87czduhsxe.fsf@dataswamp.org> (raw)
In-Reply-To: N7jzLzG--3-2@tutanota.com

carlmarcos--- via Users list for the GNU Emacs text editor wrote:

> Because it may be possible that some functions are not
> available (e.g. during testing or debugging phases), I would
> like to test whether the function `toucan' has been defined
> before I call `docboost'. What can I do?
>
> (defun toucan-usage ()
>   "TODO"
>
>   (docboost 'toucan "Usage Information"))

(Why are you using no-break space?)

What you can do?

You can ...

1. `require' the library where "toucan" is defined.

2. Use the hash/sharp-quote, #', instead of just the quote for
   toucan. (#' is `function' and ' is `quote' BTW.)

3. Byte-compile. The byte compiler will tell you if toucan
   is undefined.

-- 
underground experts united
https://dataswamp.org/~incal




  parent reply	other threads:[~2022-07-25  1:39 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-24 11:35 Executing function only if another function is defined carlmarcos--- via Users list for the GNU Emacs text editor
2022-07-24 14:33 ` [External] : " Drew Adams
     [not found] ` <SJ0PR10MB548801BBE63F2CC264989A84F3929@SJ0PR10MB5488.namprd10.prod.outlook.com-N7kcFo0----2>
2022-07-24 15:13   ` carlmarcos--- via Users list for the GNU Emacs text editor
2022-07-25  1:42     ` Emanuel Berg
2022-07-25  1:39 ` Emanuel Berg [this message]
2022-07-25  8:08   ` help as a function of a NEWS problem (was: Re: Executing function only if another function is defined) Emanuel Berg
2022-07-25 10:24   ` Executing function only if another function is defined carlmarcos--- via Users list for the GNU Emacs text editor
2022-07-25 11:14     ` Emanuel Berg
2022-07-25 11:30       ` carlmarcos--- via Users list for the GNU Emacs text editor
2022-07-25 11:45         ` Emanuel Berg
2022-07-25 11:51           ` carlmarcos--- 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=87czduhsxe.fsf@dataswamp.org \
    --to=incal@dataswamp.org \
    --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.