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* lisp/delsel.el (delete-selection-mode) (delete-selection-helper): Update and expand the doc strings. (Bug#22296) * doc/emacs/mark.texi (Using Region): Document the behavior of delete commands in Delete Selection mode. (Bug#22296) * doc/lispref/markers.texi (The Mark): Document how to add the support for Delete Selection mode to Lisp programs. (Bug#22296)
316 lines
14 KiB
EmacsLisp
316 lines
14 KiB
EmacsLisp
;;; delsel.el --- delete selection if you insert -*- lexical-binding:t -*-
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;; Copyright (C) 1992, 1997-1998, 2001-2016 Free Software Foundation,
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;; Inc.
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;; Author: Matthieu Devin <devin@lucid.com>
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;; Maintainer: emacs-devel@gnu.org
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;; Created: 14 Jul 92
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;; Keywords: convenience emulations
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;; This file makes the active region be pending delete, meaning that
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;; text inserted while the region is active will replace the region contents.
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;; This is a popular behavior of personal computers text editors.
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;; Interface:
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;; Commands which will delete the selection need a 'delete-selection
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;; property on their symbols; commands which insert text but don't
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;; have this property won't delete the selection. It can be one of
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;; the values:
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;; `yank'
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;; For commands which do a yank; ensures the region about to be
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;; deleted isn't immediately yanked back, which would make the
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;; command a no-op.
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;; `supersede'
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;; Delete the active region and ignore the current command,
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;; i.e. the command will just delete the region. This is for
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;; commands that normally delete small amounts of text, like
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;; a single character -- they will instead delete the whole
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;; active region.
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;; `kill'
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;; `kill-region' is used on the selection, rather than
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;; `delete-region'. (Text selected with the mouse will typically
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;; be yankable anyhow.)
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;; t
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;; The normal case: delete the active region prior to executing
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;; the command which will insert replacement text.
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;; FUNCTION
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;; For commands which need to dynamically determine this behavior.
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;; FUNCTION should take no argument and return one of the above
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;; values, or nil. In the latter case, FUNCTION should itself
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;; do with the active region whatever is appropriate."
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;;; Code:
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(defvar delete-selection-save-to-register nil
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"If non-nil, deleted region text is stored in this register.
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Value must be the register (key) to use.")
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;;;###autoload
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(defalias 'pending-delete-mode 'delete-selection-mode)
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;;;###autoload
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(define-minor-mode delete-selection-mode
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"Toggle Delete Selection mode.
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With a prefix argument ARG, enable Delete Selection mode if ARG
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is positive, and disable it otherwise. If called from Lisp,
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enable the mode if ARG is omitted or nil.
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When Delete Selection mode is enabled, typed text replaces the selection
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if the selection is active. Otherwise, typed text is just inserted at
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point regardless of any selection. Also, commands that normally delete
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just one character will delete the entire selection instead.
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See `delete-selection-helper' and `delete-selection-pre-hook' for
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information on adapting behavior of commands in Delete Selection mode."
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:global t :group 'editing-basics
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(if (not delete-selection-mode)
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(remove-hook 'pre-command-hook 'delete-selection-pre-hook)
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(add-hook 'pre-command-hook 'delete-selection-pre-hook)))
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(defvar delsel--replace-text-or-position nil)
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(defun delete-active-region (&optional killp)
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"Delete the active region.
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If KILLP in not-nil, the active region is killed instead of deleted."
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(cond
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(killp
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;; Don't allow `kill-region' to change the value of `this-command'.
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(let (this-command)
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(kill-region (point) (mark) t)))
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(delete-selection-save-to-register
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(set-register delete-selection-save-to-register
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(funcall region-extract-function t))
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(setq delsel--replace-text-or-position
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(cons (current-buffer)
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(and (consp buffer-undo-list) (car buffer-undo-list)))))
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(t
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(funcall region-extract-function 'delete-only))))
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(defun delete-selection-repeat-replace-region (arg)
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"Repeat replacing text of highlighted region with typed text.
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Search for the next stretch of text identical to the region last replaced
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by typing text over it and replaces it with the same stretch of text.
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With ARG, repeat that many times. `C-u' means until end of buffer."
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(interactive "P")
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(let ((old-text (and delete-selection-save-to-register
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(get-register delete-selection-save-to-register)))
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(count (if (consp arg) (point-max)
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(prefix-numeric-value current-prefix-arg))))
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(if (not (and old-text
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(> (length old-text) 0)
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(or (stringp delsel--replace-text-or-position)
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(buffer-live-p (car delsel--replace-text-or-position)))))
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(message "No known previous replacement")
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;; If this is the first use after overwriting regions,
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;; find the replacement text by looking at the undo list.
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(when (consp delsel--replace-text-or-position)
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(let ((buffer (car delsel--replace-text-or-position))
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(elt (cdr delsel--replace-text-or-position)))
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(setq delsel--replace-text-or-position nil)
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(with-current-buffer buffer
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(save-restriction
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(widen)
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;; Find the text that replaced the region via the undo list.
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(let ((ul buffer-undo-list) u s e)
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(when elt
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(while (consp ul)
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(setq u (car ul) ul (cdr ul))
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(cond
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((eq u elt) ;; got it
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(setq ul nil))
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((and (consp u) (integerp (car u)) (integerp (cdr u)))
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(if (and s (= (cdr u) s))
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(setq s (car u))
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(setq s (car u) e (cdr u)))))))
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(cond ((and s e (<= s e) (= s (mark t)))
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(setq delsel--replace-text-or-position
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(filter-buffer-substring s e))
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(set-text-properties
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0 (length delsel--replace-text-or-position)
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nil delsel--replace-text-or-position))
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((and (null s) (eq u elt)) ;; Nothing inserted.
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(setq delsel--replace-text-or-position ""))
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(t
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(message "Cannot locate replacement text"))))))))
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(while (and (> count 0)
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delsel--replace-text-or-position
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(search-forward old-text nil t))
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(replace-match delsel--replace-text-or-position nil t)
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(setq count (1- count))))))
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(defun delete-selection-helper (type)
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"Delete selection according to TYPE:
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`yank'
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For commands which do a yank; ensures the region about to be
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deleted isn't immediately yanked back, which would make the
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command a no-op.
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`supersede'
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Delete the active region and ignore the current command,
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i.e. the command will just delete the region. This is for
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commands that normally delete small amounts of text, like
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a single character -- they will instead delete the whole
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active region.
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`kill'
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`kill-region' is used on the selection, rather than
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`delete-region'. (Text selected with the mouse will typically
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be yankable anyhow.)
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t
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The normal case: delete the active region prior to executing
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the command which will insert replacement text.
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FUNCTION
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For commands which need to dynamically determine this behavior.
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FUNCTION should take no argument and return one of the above
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values, or nil. In the latter case, FUNCTION should itself
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do with the active region whatever is appropriate."
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(condition-case data
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(cond ((eq type 'kill) ;Deprecated, backward compatibility.
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(delete-active-region t)
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(if (and overwrite-mode
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(eq this-command 'self-insert-command))
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(let ((overwrite-mode nil))
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(self-insert-command
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(prefix-numeric-value current-prefix-arg))
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(setq this-command 'ignore))))
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((eq type 'yank)
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;; Before a yank command, make sure we don't yank the
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;; head of the kill-ring that really comes from the
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;; currently active region we are going to delete.
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;; That would make yank a no-op.
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(when (and (string= (buffer-substring-no-properties
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(point) (mark))
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(car kill-ring))
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(fboundp 'mouse-region-match)
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(mouse-region-match))
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(current-kill 1))
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(let ((pos (copy-marker (region-beginning))))
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(delete-active-region)
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;; If the region was, say, rectangular, make sure we yank
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;; from the top, to "replace".
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(goto-char pos)))
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((eq type 'supersede)
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(let ((empty-region (= (point) (mark))))
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(delete-active-region)
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(unless empty-region
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(setq this-command 'ignore))))
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((functionp type) (delete-selection-helper (funcall type)))
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(type
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(delete-active-region)
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(if (and overwrite-mode
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(eq this-command 'self-insert-command))
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(let ((overwrite-mode nil))
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(self-insert-command
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(prefix-numeric-value current-prefix-arg))
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(setq this-command 'ignore)))))
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;; If ask-user-about-supersession-threat signals an error,
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;; stop safe_run_hooks from clearing out pre-command-hook.
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(file-supersession (message "%s" (cadr data)) (ding))
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(text-read-only
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;; This signal may come either from `delete-active-region' or
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;; `self-insert-command' (when `overwrite-mode' is non-nil).
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;; To avoid clearing out `pre-command-hook' we handle this case
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;; by issuing a simple message. Note, however, that we do not
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;; handle all related problems: When read-only text ends before
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;; the end of the region, the latter is not deleted but any
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;; subsequent insertion will succeed. We could avoid this case
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;; by doing a (setq this-command 'ignore) here. This would,
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;; however, still not handle the case where read-only text ends
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;; precisely where the region starts: In that case the deletion
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;; would succeed but the subsequent insertion would fail with a
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;; text-read-only error. To handle that case we would have to
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;; investigate text properties at both ends of the region and
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;; skip the deletion when inserting text is forbidden there.
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(message "Text is read-only") (ding))))
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(defun delete-selection-pre-hook ()
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"Function run before commands that delete selections are executed.
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Commands which will delete the selection need a `delete-selection'
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property on their symbol; commands which insert text but don't
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have this property won't delete the selection.
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See `delete-selection-helper'."
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(when (and delete-selection-mode (use-region-p)
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(not buffer-read-only))
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(delete-selection-helper (and (symbolp this-command)
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(get this-command 'delete-selection)))))
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(defun delete-selection-uses-region-p ()
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"Return t when the current command will be using the region
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rather than having `delete-selection' delete it, nil otherwise.
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This function is intended for use as the value of the
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`delete-selection' property of a command, and shouldn't be used
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for anything else."
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(not (run-hook-with-args-until-success
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'self-insert-uses-region-functions)))
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(put 'self-insert-command 'delete-selection 'delete-selection-uses-region-p)
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(put 'insert-char 'delete-selection t)
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(put 'quoted-insert 'delete-selection t)
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(put 'yank 'delete-selection 'yank)
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(put 'clipboard-yank 'delete-selection 'yank)
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(put 'insert-register 'delete-selection t)
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;; delete-backward-char and delete-forward-char already delete the selection by
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;; default, but not delete-char.
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(put 'delete-char 'delete-selection 'supersede)
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(put 'reindent-then-newline-and-indent 'delete-selection t)
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(put 'newline-and-indent 'delete-selection t)
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(put 'newline 'delete-selection t)
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(put 'electric-newline-and-maybe-indent 'delete-selection t)
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(put 'open-line 'delete-selection t)
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;; This is very useful for canceling a selection in the minibuffer without
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;; aborting the minibuffer.
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(defun minibuffer-keyboard-quit ()
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"Abort recursive edit.
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In Delete Selection mode, if the mark is active, just deactivate it;
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then it takes a second \\[keyboard-quit] to abort the minibuffer."
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(interactive)
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(if (and delete-selection-mode (region-active-p))
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(setq deactivate-mark t)
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(abort-recursive-edit)))
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(define-key minibuffer-local-map "\C-g" 'minibuffer-keyboard-quit)
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(define-key minibuffer-local-ns-map "\C-g" 'minibuffer-keyboard-quit)
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(define-key minibuffer-local-completion-map "\C-g" 'minibuffer-keyboard-quit)
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(define-key minibuffer-local-must-match-map "\C-g" 'minibuffer-keyboard-quit)
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(define-key minibuffer-local-isearch-map "\C-g" 'minibuffer-keyboard-quit)
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(defun delsel-unload-function ()
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"Unload the Delete Selection library."
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(define-key minibuffer-local-map "\C-g" 'abort-recursive-edit)
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(define-key minibuffer-local-ns-map "\C-g" 'abort-recursive-edit)
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(define-key minibuffer-local-completion-map "\C-g" 'abort-recursive-edit)
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(define-key minibuffer-local-must-match-map "\C-g" 'abort-recursive-edit)
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(define-key minibuffer-local-isearch-map "\C-g" 'abort-recursive-edit)
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(dolist (sym '(self-insert-command insert-char quoted-insert yank
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clipboard-yank insert-register newline-and-indent
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reindent-then-newline-and-indent newline open-line))
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(put sym 'delete-selection nil))
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;; continue standard unloading
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nil)
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(provide 'delsel)
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;;; delsel.el ends here
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