From: Chong Yidong <cyd@stupidchicken.com>
To: emacs-devel@gnu.org
Subject: Proposal for DEL to delete the active region
Date: Fri, 30 Apr 2010 23:23:22 -0400 [thread overview]
Message-ID: <87iq78uwyd.fsf@stupidchicken.com> (raw)
Here is a proposal for DEL to delete the region when transient-mark-mode
is enabled. DEL already does this in delete-selection-mode; the idea
here is to move this behavior into transient-mark-mode proper.
This involves getting rid of `mouse-region-delete-keys', moving
`delete-backward-char' from C to Lisp, and introducing a new variable
`delete-backward-char-delete-region'. Its default value, t, means that
`delete-backward-char' will delete the active region.
Conceptually, this puts `delete-backward-char-delete-region' on the same
footing as other user commands that "act on the region" under Transient
Mark mode. The additional benefit is getting rid of the
`mouse-region-delete-keys' hack, so that DEL does the same thing for all
active regions.
Something similar would be done with delete-char (not shown in this
patch), so that [delete] deletes active regions too.
Comments, and suggestions for different approaches, welcome.
*** lisp/simple.el 2010-04-28 15:18:37 +0000
--- lisp/simple.el 2010-05-01 03:12:28 +0000
***************
*** 837,842 ****
--- 837,891 ----
(overlay-recenter (point))
(recenter -3))))
+ (defcustom delete-backward-char-delete-region t
+ "If non-nil, `delete-backward-char' deletes active regions.
+ This has an effect only when Transient Mark mode is enabled.
+ If the value is the symbol `kill', `delete-backward-char' kills
+ the active region instead of deleting it."
+ :type '(choice (const :tag "Delete region" t)
+ (const :tag "Kill region" kill)
+ (const :tag "Do not delete region" nil))
+ :group 'editing
+ :version "24.1")
+
+ (defun delete-backward-char (n killflag)
+ "Delete the previous N characters (following if N is negative).
+ KILLFLAG, if non-nil, means kill instead (save in kill ring).
+ Interactively, N is the prefix arg, and KILLFLAG is set if N is
+ explicitly specified.
+
+ If Transient Mark mode is enabled, the mark is active, and N is 1,
+ delete the text in the region and deactivate the mark instead.
+ To disable this, set `delete-backward-char-delete-region' to nil."
+ (interactive "p\nP")
+ (unless (integerp n)
+ (signal 'wrong-type-argument (list 'integerp n)))
+ (cond ((and (use-region-p)
+ delete-backward-char-delete-region
+ (= n 1))
+ (if (eq delete-backward-char-delete-region 'kill)
+ (kill-region (region-beginning) (region-end))
+ (delete-region (region-beginning) (region-end))))
+ ((and overwrite-mode
+ (> n 0)
+ (null (memq (char-before) '(?\t ?\n)))
+ (null (eobp))
+ (null (eq (char-after) ?\n)))
+ ;; In overwrite mode, back over columns while clearing them
+ ;; out, unless at end of line.
+ (let* ((ocol (current-column))
+ (val (delete-char (- n) killflag)))
+ (save-excursion
+ (insert-char ?\s (- ocol (current-column)) nil))))
+ (killflag
+ (kill-backward-chars n))
+ ((< (min (point) (- (point) n)) (point-min))
+ (signal 'beginning-of-buffer nil))
+ ((> (max (point) (- (point) n)) (point-max))
+ (signal 'beginning-of-buffer nil))
+ (t
+ (delete-region (- (point) n) (point)))))
+
(defun mark-whole-buffer ()
"Put point at beginning and mark at end of buffer.
You probably should not use this function in Lisp programs;
*** src/cmds.c 2010-03-31 04:14:08 +0000
--- src/cmds.c 2010-05-01 00:06:40 +0000
***************
*** 265,322 ****
return Qnil;
}
- DEFUN ("delete-backward-char", Fdelete_backward_char, Sdelete_backward_char,
- 1, 2, "p\nP",
- doc: /* Delete the previous N characters (following if N is negative).
- Optional second arg KILLFLAG non-nil means kill instead (save in kill ring).
- Interactively, N is the prefix arg, and KILLFLAG is set if
- N was explicitly specified. */)
- (n, killflag)
- Lisp_Object n, killflag;
- {
- Lisp_Object value;
- int deleted_special = 0;
- int pos, pos_byte, i;
-
- CHECK_NUMBER (n);
-
- /* See if we are about to delete a tab or newline backwards. */
- pos = PT;
- pos_byte = PT_BYTE;
- for (i = 0; i < XINT (n) && pos_byte > BEGV_BYTE; i++)
- {
- int c;
-
- DEC_BOTH (pos, pos_byte);
- c = FETCH_BYTE (pos_byte);
- if (c == '\t' || c == '\n')
- {
- deleted_special = 1;
- break;
- }
- }
-
- /* In overwrite mode, back over columns while clearing them out,
- unless at end of line. */
- if (XINT (n) > 0
- && ! NILP (current_buffer->overwrite_mode)
- && ! deleted_special
- && ! (PT == ZV || FETCH_BYTE (PT_BYTE) == '\n'))
- {
- int column = (int) current_column (); /* iftc */
-
- value = Fdelete_char (make_number (-XINT (n)), killflag);
- i = column - (int) current_column (); /* iftc */
- Finsert_char (make_number (' '), make_number (i), Qnil);
- /* Whitespace chars are ASCII chars, so we can simply subtract. */
- SET_PT_BOTH (PT - i, PT_BYTE - i);
- }
- else
- value = Fdelete_char (make_number (-XINT (n)), killflag);
-
- return value;
- }
-
static int nonundocount;
/* Note that there's code in command_loop_1 which typically avoids
--- 265,270 ----
***************
*** 625,631 ****
defsubr (&Send_of_line);
defsubr (&Sdelete_char);
- defsubr (&Sdelete_backward_char);
defsubr (&Sself_insert_command);
}
--- 573,578 ----
*** lisp/mouse.el 2010-01-13 08:35:10 +0000
--- lisp/mouse.el 2010-04-30 23:30:48 +0000
***************
*** 1263,1273 ****
;; Momentarily show where the mark is, if highlighting doesn't show it.
- (defcustom mouse-region-delete-keys '([delete] [deletechar] [backspace])
- "List of keys that should cause the mouse region to be deleted."
- :group 'mouse
- :type '(repeat key-sequence))
-
(defun mouse-show-mark ()
(let ((inhibit-quit t)
(echo-keystrokes 0)
--- 1263,1268 ----
***************
*** 1297,1304 ****
'vertical-scroll-bar))
(and (memq 'down (event-modifiers event))
(not (key-binding key))
! (not (mouse-undouble-last-event events))
! (not (member key mouse-region-delete-keys)))))
(and (consp event)
(or (eq (car event) 'switch-frame)
(eq (posn-point (event-end event))
--- 1292,1298 ----
'vertical-scroll-bar))
(and (memq 'down (event-modifiers event))
(not (key-binding key))
! (not (mouse-undouble-last-event events)))))
(and (consp event)
(or (eq (car event) 'switch-frame)
(eq (posn-point (event-end event))
***************
*** 1311,1332 ****
(setq events nil)))))))
;; If we lost the selection, just turn off the highlighting.
(unless ignore
! ;; For certain special keys, delete the region.
! (if (member key mouse-region-delete-keys)
! (progn
! ;; Since notionally this is a separate command,
! ;; run all the hooks that would be run if it were
! ;; executed separately.
! (run-hooks 'post-command-hook)
! (setq last-command this-command)
! (setq this-original-command 'delete-region)
! (setq this-command (or (command-remapping this-original-command)
! this-original-command))
! (run-hooks 'pre-command-hook)
! (call-interactively this-command))
! ;; Otherwise, unread the key so it gets executed normally.
! (setq unread-command-events
! (nconc events unread-command-events))))
(setq quit-flag nil)
(unless transient-mark-mode
(delete-overlay mouse-drag-overlay))))
--- 1305,1313 ----
(setq events nil)))))))
;; If we lost the selection, just turn off the highlighting.
(unless ignore
! ;; Unread the key so it gets executed normally.
! (setq unread-command-events
! (nconc events unread-command-events)))
(setq quit-flag nil)
(unless transient-mark-mode
(delete-overlay mouse-drag-overlay))))
next reply other threads:[~2010-05-01 3:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-01 3:23 Chong Yidong [this message]
2010-05-02 2:54 ` Proposal for DEL to delete the active region Stefan Monnier
2010-05-02 6:04 ` Thierry Volpiatto
2010-05-02 14:34 ` Chong Yidong
2010-05-03 6:00 ` Richard Stallman
2010-05-03 17:12 ` Stefan Monnier
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