;;; delsel.el --- delete selection if you insert
-;; Copyright (C) 1992, 1997-1998, 2001-2011 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1997-1998, 2001-2013 Free Software Foundation,
+;; Inc.
;; Author: Matthieu Devin <devin@lucid.com>
;; Maintainer: FSF
;; `kill-region' is used on the selection, rather than
;; `delete-region'. (Text selected with the mouse will typically
;; be yankable anyhow.)
-;; non-nil
+;; t
;; The normal case: delete the active region prior to executing
;; the command which will insert replacement text.
+;; <function>
+;; For commands which need to dynamically determine this behaviour.
+;; The function should return one of the above values or nil.
;;; Code:
;;;###autoload
(define-minor-mode delete-selection-mode
"Toggle Delete Selection mode.
-With prefix ARG, turn Delete Selection mode on if ARG is
-positive, off if ARG is not positive.
+With a prefix argument ARG, enable Delete Selection mode if ARG
+is positive, and disable it otherwise. If called from Lisp,
+enable the mode if ARG is omitted or nil.
When Delete Selection mode is enabled, Transient Mark mode is also
enabled and typed text replaces the selection if the selection is
(transient-mark-mode t)))
(defun delete-active-region (&optional killp)
+ "Delete the active region.
+If KILLP in not-nil, the active region is killed instead of deleted."
(if killp
(kill-region (point) (mark))
(delete-region (point) (mark)))
t)
+(defun delete-selection-helper (type)
+ "Delete selection according to TYPE:
+ `yank'
+ For commands which do a yank; ensures the region about to be
+ deleted isn't yanked.
+ `supersede'
+ Delete the active region and ignore the current command,
+ i.e. the command will just delete the region.
+ `kill'
+ `kill-region' is used on the selection, rather than
+ `delete-region'. (Text selected with the mouse will typically
+ be yankable anyhow.)
+ t
+ The normal case: delete the active region prior to executing
+ the command which will insert replacement text.
+ FUNCTION
+ For commands which need to dynamically determine this behaviour.
+ FUNCTION should take no argument and return one of the above values or nil."
+ (condition-case data
+ (cond ((eq type 'kill)
+ (delete-active-region t))
+ ((eq type 'yank)
+ ;; Before a yank command, make sure we don't yank the
+ ;; head of the kill-ring that really comes from the
+ ;; currently active region we are going to delete.
+ ;; That would make yank a no-op.
+ (when (and (string= (buffer-substring-no-properties
+ (point) (mark))
+ (car kill-ring))
+ (fboundp 'mouse-region-match)
+ (mouse-region-match))
+ (current-kill 1))
+ (delete-active-region))
+ ((eq type 'supersede)
+ (let ((empty-region (= (point) (mark))))
+ (delete-active-region)
+ (unless empty-region
+ (setq this-command 'ignore))))
+ ((functionp type) (delete-selection-helper (funcall type)))
+ (type
+ (delete-active-region)
+ (if (and overwrite-mode
+ (eq this-command 'self-insert-command))
+ (let ((overwrite-mode nil))
+ (self-insert-command
+ (prefix-numeric-value current-prefix-arg))
+ (setq this-command 'ignore)))))
+ ;; If ask-user-about-supersession-threat signals an error,
+ ;; stop safe_run_hooks from clearing out pre-command-hook.
+ (file-supersession (message "%s" (cadr data)) (ding))
+ (text-read-only
+ ;; This signal may come either from `delete-active-region' or
+ ;; `self-insert-command' (when `overwrite-mode' is non-nil).
+ ;; To avoid clearing out `pre-command-hook' we handle this case
+ ;; by issuing a simple message. Note, however, that we do not
+ ;; handle all related problems: When read-only text ends before
+ ;; the end of the region, the latter is not deleted but any
+ ;; subsequent insertion will succeed. We could avoid this case
+ ;; by doing a (setq this-command 'ignore) here. This would,
+ ;; however, still not handle the case where read-only text ends
+ ;; precisely where the region starts: In that case the deletion
+ ;; would succeed but the subsequent insertion would fail with a
+ ;; text-read-only error. To handle that case we would have to
+ ;; investigate text properties at both ends of the region and
+ ;; skip the deletion when inserting text is forbidden there.
+ (message "Text is read-only") (ding))))
+
(defun delete-selection-pre-hook ()
- (when (and delete-selection-mode transient-mark-mode mark-active
+ "Function run before commands that delete selections are executed.
+Commands which will delete the selection need a `delete-selection'
+property on their symbol; commands which insert text but don't
+have this property won't delete the selection.
+See `delete-selection-helper'."
+ (when (and delete-selection-mode (use-region-p)
(not buffer-read-only))
- (let ((type (and (symbolp this-command)
- (get this-command 'delete-selection))))
- (condition-case data
- (cond ((eq type 'kill)
- (delete-active-region t))
- ((eq type 'yank)
- ;; Before a yank command, make sure we don't yank the
- ;; head of the kill-ring that really comes from the
- ;; currently active region we are going to delete.
- ;; That would make yank a no-op.
- (when (and (string= (buffer-substring-no-properties (point) (mark))
- (car kill-ring))
- (fboundp 'mouse-region-match)
- (mouse-region-match))
- (current-kill 1))
- (delete-active-region))
- ((eq type 'supersede)
- (let ((empty-region (= (point) (mark))))
- (delete-active-region)
- (unless empty-region
- (setq this-command 'ignore))))
- (type
- (delete-active-region)
- (if (and overwrite-mode (eq this-command 'self-insert-command))
- (let ((overwrite-mode nil))
- (self-insert-command (prefix-numeric-value current-prefix-arg))
- (setq this-command 'ignore)))))
- (file-supersession
- ;; If ask-user-about-supersession-threat signals an error,
- ;; stop safe_run_hooks from clearing out pre-command-hook.
- (and (eq inhibit-quit 'pre-command-hook)
- (setq inhibit-quit 'delete-selection-dummy))
- (signal 'file-supersession (cdr data)))
- (text-read-only
- ;; This signal may come either from `delete-active-region' or
- ;; `self-insert-command' (when `overwrite-mode' is non-nil).
- ;; To avoid clearing out `pre-command-hook' we handle this case
- ;; by issuing a simple message. Note, however, that we do not
- ;; handle all related problems: When read-only text ends before
- ;; the end of the region, the latter is not deleted but any
- ;; subsequent insertion will succeed. We could avoid this case
- ;; by doing a (setq this-command 'ignore) here. This would,
- ;; however, still not handle the case where read-only text ends
- ;; precisely where the region starts: In that case the deletion
- ;; would succeed but the subsequent insertion would fail with a
- ;; text-read-only error. To handle that case we would have to
- ;; investigate text properties at both ends of the region and
- ;; skip the deletion when inserting text is forbidden there.
- (message "Text is read-only") (ding))))))
-
-(put 'self-insert-command 'delete-selection t)
+ (delete-selection-helper (and (symbolp this-command)
+ (get this-command 'delete-selection)))))
+
+(put 'self-insert-command 'delete-selection
+ (lambda ()
+ (not (run-hook-with-args-until-success
+ 'self-insert-uses-region-functions))))
+
(put 'self-insert-iso 'delete-selection t)
(put 'yank 'delete-selection 'yank)
(put 'newline 'delete-selection t)
(put 'open-line 'delete-selection 'kill)
-;; This is very useful for cancelling a selection in the minibuffer without
+;; This is very useful for canceling a selection in the minibuffer without
;; aborting the minibuffer.
(defun minibuffer-keyboard-quit ()
"Abort recursive edit.