From: Joost Kremers <joostkremers@yahoo.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Problems with keybindings for functions with arguments
Date: 8 Mar 2013 18:39:45 GMT [thread overview]
Message-ID: <slrnkjkc3h.a6b.joostkremers@j.kremers4.news.arnhem.chello.nl> (raw)
In-Reply-To: mailman.21680.1362751341.855.help-gnu-emacs@gnu.org
Thorsten Jolitz wrote:
>
> Hi List,
>
> say I have a function that recieves an integer in range 1 to 8 as
> argument and does different things depending on the argument value:
>
> ,---------------------------
>| (defun navi-show-headers (level)
>| "Act conditional on LEVEL"
>| (do-stuff level))
> `---------------------------
>
> These "things" are useful enough that each of the eight possibilities
> should get its own keybindings as user-command - a one-key binding in a
> 'special-mode' (read-only buffer like e.g. dired).
>
> Say these keybindings should simply be "1", "2", ... , "8".
>
> #### Question 1 ####
>
> So how can I make this a (interactive) command that takes one argument,
> but doesn't ask the user about it and does not force the user to give
> prefix-args all the time (like 'C-1' e.g.)?
For a package of mine (Ebib), Steve Youngs (of SXEmacs fame) once
offered some code to solve the same kind of problem. His approach was to
define a command that takes the key with which it is called as its
argument:
,----
| (defun ebib-switch-to-database-nth (key)
| (interactive (list (if (featurep 'xemacs)
| (event-key last-command-event)
| last-command-event)))
| (ebib-switch-to-database (- (if (featurep 'xemacs)
| (char-to-int key)
| key) 48)))
`----
Pretty nifty, I must say, and not something I would ever have thought of
myself. ;-) You can then bind all number keys to this function with:
,----
| (mapc #'(lambda (key)
| (define-key ebib-index-mode-map (format "%d" key)
| 'ebib-switch-to-database-nth))
| '(1 2 3 4 5 6 7 8 9))
`----
This way, `C-h m' shows the following:
,----
| 1 .. 9 ebib-switch-to-database-nth
`----
which in my case is sufficient, don't know if it would be for you.
> #### question 2 ####
>
> What if I want an optional prefix argument and act conditional on its
> existence or value like this
I think it should be possible to incorporate this by using the variabe
`current-prefix-arg' (see Info node "(elisp) Prefix Command Arguments").
Something like this should work (untested):
,----
| (defun navi-show-headers (key prefix)
| (interactive (list (if (featurep 'xemacs)
| (event-key last-command-event)
| last-command-event)
| current-prefix-arg))
| (code...)
`----
(BTW, I don't know if current-prefix-arg can also be used in XEmacs. I
stopped testing for XEmacs compatibility a long time ago and never had
any complaints, so I don't know how to quickly test that.)
HTH
--
Joost Kremers joostkremers@yahoo.com
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)
next parent reply other threads:[~2013-03-08 18:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.21680.1362751341.855.help-gnu-emacs@gnu.org>
2013-03-08 18:39 ` Joost Kremers [this message]
2013-03-09 13:35 ` Problems with keybindings for functions with arguments Thorsten Jolitz
[not found] ` <mailman.21759.1362836184.855.help-gnu-emacs@gnu.org>
2013-03-10 13:26 ` Joost Kremers
2013-03-08 14:01 Thorsten Jolitz
2013-03-08 14:20 ` Jambunathan K
2013-03-08 14:56 ` Thorsten Jolitz
2013-03-08 15:03 ` Drew Adams
2013-03-08 16:04 ` Thorsten Jolitz
2013-03-08 16:17 ` Nicolas Richard
2013-03-08 22:26 ` Nicolas Richard
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