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Re: bug#7234: 24.0.50; strange message after text-scale-adjust
From: |
Stefan Monnier |
Subject: |
Re: bug#7234: 24.0.50; strange message after text-scale-adjust |
Date: |
Mon, 18 Oct 2010 10:17:53 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) |
> It would be better that read-event call in
> text-scale-adjust has some prompt:
> e.g. (read-event "+,-,0 for further adjustment: ")
Agreed.
> For non-interactive use, you should probably also be using
> `text-scale-set' or `text-scale-increase' instead.
BTW, I've been playing around with an alternative implementation for
such things. The reason is that the use of
read-event/read-char/read-key has surprising side-effects: in those
cases I'm concerned with, the user expects that the command is already
finished and the behavior is somewhat consistent with that expectation,
but not completely: indeed typing "any" key sequence (except for a few
special ones) runs the usual corresponding command, but OTOH
post-command-hook and friends aren't run when expected.
So, instead I use a new function set-temporary-overlay-map which sets up
a keymap that's only active for a short period of time (by default just
for the next key-sequence):
Using submit branch file:///home/monnier/src/emacs/bzr/trunk/
=== modified file 'lisp/face-remap.el'
*** lisp/face-remap.el 2010-03-14 21:15:02 +0000
--- lisp/face-remap.el 2010-08-21 07:43:23 +0000
***************
*** 294,319 ****
`text-scale-decrease' may be more appropriate."
(interactive "p")
(let ((first t)
- (step t)
(ev last-command-event)
(echo-keystrokes nil))
! (while step
! (let ((base (event-basic-type ev)))
! (cond ((or (eq base ?+) (eq base ?=))
! (setq step inc))
! ((eq base ?-)
! (setq step (- inc)))
! ((eq base ?0)
! (setq step 0))
! (first
! (setq step inc))
! (t
! (setq step nil))))
! (when step
(text-scale-increase step)
! (setq inc 1 first nil)
! (setq ev (read-event))))
! (push ev unread-command-events)))
;; ----------------------------------------------------------------
--- 294,317 ----
`text-scale-decrease' may be more appropriate."
(interactive "p")
(let ((first t)
(ev last-command-event)
(echo-keystrokes nil))
! (let* ((base (event-basic-type ev))
! (step
! (case base
! ((?+ ?=) inc)
! (?- (- inc))
! (?0 0)
! (t inc))))
(text-scale-increase step)
! (set-temporary-overlay-map
! (let ((map (make-sparse-keymap)))
! (define-key map [?=] 'text-scale-increase)
! (define-key map [?0] (lambda () (interactive) (text-scale-increase
0)))
! (define-key map [?+] 'text-scale-increase)
! (define-key map [?-] 'text-scale-decrease)
! map)
! t))))
;; ----------------------------------------------------------------
Currently, my implementation of set-temporary-overlay-map (see appended)
is not 100% satisfactory, so it may require some changes to the C code,
but it already works well in practice.
Stefan
(defun set-temporary-overlay-map (map &optional keep-pred)
(let* ((clearfunsym (make-symbol "clear-temporary-overlay-map"))
(overlaysym (make-symbol "t"))
(alist (list (cons overlaysym map)))
(clearfun
`(lambda ()
(unless ,(cond ((null keep-pred) nil)
((eq t keep-pred)
`(eq this-command
(lookup-key ',map
(this-command-keys-vector))))
(t `(funcall ',keep-pred)))
(remove-hook 'pre-command-hook ',clearfunsym)
(cancel-timer ,overlaysym)
(setq ,overlaysym nil)
(save-current-buffer
(if (buffer-live-p ',(current-buffer))
(set-buffer ',(current-buffer)))
(setq emulation-mode-map-alists
(delq ',alist emulation-mode-map-alists)))))))
(fset clearfunsym clearfun)
(add-hook 'pre-command-hook clearfunsym)
;; Sadly, pre-command-hook is occasionally set to nil (if one of its
;; functions signals an error). We should improve safe_run_hooks so as to
;; only remove the offending function rather than set the whole thing to
;; nil, but in the mean time, let's use an auxiliary timer to monitor
;; pre-command-hook to make sure we don't end up with a lingering
;; overlay-map which could otherwise render Emacs unusable.
(set overlaysym
(run-with-idle-timer
0 t
`(lambda ()
(if (memq ',clearfunsym
(default-value 'pre-command-hook))
nil
(message "clear-temporary-overlay-map lost in pre-command-hook!")
(,clearfunsym)))))
;; FIXME: That's the keymaps with highest precedence, except for
;; the `keymap' text-property ;-(
(push alist emulation-mode-map-alists)))
- Re: bug#7234: 24.0.50; strange message after text-scale-adjust,
Stefan Monnier <=