From: storm@cua.dk (Kim F. Storm)
Subject: Suggestion: Simple way to make conditional key bindings.
Date: 23 Aug 2002 14:05:13 +0200 [thread overview]
Message-ID: <5x4rdlbx1i.fsf@kfs2.cua.dk> (raw)
Sometimes you would like a specific key binding to be controlled
by some global or local state, but you really don't want to mess
with minor-mode keymaps etc.
The following method - illustrated by example - is simple, yet very
powerful and flexible.
The basic idea is to interpret a '(cond ...) binding "the natural way":
(setq a nil b nil c nil)
(global-set-key [f11]
'(cond
(a delete-char)
(b find-file)
(c nil)
(t (keymap (?a . "abc") (?b . "bcd")))))
[f11 a] => "abc"
[f11 b] => "bcd"
[f11 c] => undefined
(setq c t)
[f11] => undefined
(setq b t)
[f11] => find-char
(setq a t)
[f11] => delete-char
Here is a patch [against a fairly old keymap.c] to implement this feature.
The simplicity of the approach is proven by the size of the patch :-)
One use would be to bind C-y to `yank' except when the first element
in the kill-ring is a table, in which case we want to run
`yank-with-properties':
(global-set-key "\C-y"
'(cond
((and kill-ring (table-recognize-table (car kill-ring)))
yank-with-properties)
(t yank)))
One advantage (IMO) is that C-h k C-y will report yank or
yank-with-properties depending on the actual function taken if
you hit C-y.
WDYT ?
Index: keymap.c
===================================================================
RCS file: /cvs/emacs/src/keymap.c,v
retrieving revision 1.260
diff -c -r1.260 keymap.c
*** keymap.c 10 May 2002 23:57:14 -0000 1.260
--- keymap.c 13 May 2002 10:08:23 -0000
***************
*** 93,98 ****
--- 93,99 ----
Lisp_Object Vdefine_key_rebound_commands;
Lisp_Object Qkeymapp, Qkeymap, Qnon_ascii, Qmenu_item, Qremap;
+ Lisp_Object Qcond;
/* Alist of elements like (DEL . "\d"). */
static Lisp_Object exclude_keys;
***************
*** 690,695 ****
--- 691,718 ----
return object;
}
+ /* If the keymap contents looks like (cond (COND DEFN)...)
+ then find first non-nil COND and use its DEFN.*/
+
+ else if (EQ (XCAR (object), Qcond))
+ {
+ register Lisp_Object args = XCDR (object);
+ object = Qnil;
+ for ( ; CONSP (args); args = XCDR (args))
+ {
+ register Lisp_Object clause, val;
+ clause = XCAR (args);
+ if (!CONSP (clause) || !CONSP (XCDR (clause)))
+ continue;
+ val = menu_item_eval_property (XCAR (clause));
+ if (!NILP (val))
+ {
+ object = XCAR (XCDR (clause));
+ break;
+ }
+ }
+ }
+
/* If the keymap contents looks like (STRING . DEFN), use DEFN.
Keymap alist elements like (CHAR MENUSTRING . DEFN)
will be used by HierarKey menus. */
***************
*** 3650,3655 ****
--- 3673,3681 ----
Qremap = intern ("remap");
staticpro (&Qremap);
+
+ Qcond = intern ("cond");
+ staticpro (&Qcond);
remap_command_vector = Fmake_vector (make_number (2), Qremap);
staticpro (&remap_command_vector);
--
Kim F. Storm <storm@cua.dk> http://www.cua.dk
next reply other threads:[~2002-08-23 12:05 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-23 12:05 Kim F. Storm [this message]
2002-08-26 0:36 ` Suggestion: Simple way to make conditional key bindings Richard Stallman
2002-08-26 16:21 ` Stefan Monnier
2002-08-30 10:27 ` Robert J. Chassell
-- strict thread matches above, loose matches on Subject: below --
2002-08-23 12:52 David PONCE
[not found] <3D49FF140074EFAE@mel-rta7.wanadoo.fr>
2002-08-23 13:16 ` Kim F. Storm
2002-08-23 17:22 ` Stefan Monnier
2002-08-25 23:33 ` Kim F. Storm
2002-08-26 15:47 ` Stefan Monnier
2002-08-26 19:33 ` Miles Bader
2002-08-27 19:05 ` Richard Stallman
2002-08-27 22:58 ` Kim F. Storm
2002-08-28 23:32 ` Richard Stallman
2002-08-29 8:54 ` Kim F. Storm
2002-08-28 1:00 ` Miles Bader
2002-08-28 1:22 ` Stefan Monnier
2002-08-27 11:23 ` Kim F. Storm
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
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5x4rdlbx1i.fsf@kfs2.cua.dk \
--to=storm@cua.dk \
/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 public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).