--- /dev/null
+;;; refill.el --- `auto-fill' by refilling paragraphs on changes
+
+;; Copyright (C) 2000 Free Software Foundation, Inc.
+
+;; Author: Dave Love <fx@gnu.org>
+;; Keywords: wp
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2 of the License, or
+;; (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program; if not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;; Provides a mode where paragraphs are refilled after changes in them
+;; (using `after-change-hooks'). This gives something akin to typical
+;; word processor-style filling. We restrict refilling due to
+;; self-insertion to the characters which trigger auto-fill.
+
+;; It partly satisfies a todo item in enriched.el for some value of
+;; `without slowing down editing too much'. It doesn't attempt to do
+;; anything (using `window-size-change-functions'?) about resizing
+;; windows -- who cares?
+
+;; This implementation is probably fragile and missing some special
+;; cases -- not extensively tested. Yanking paragraph breaks, for
+;; instance, won't DTRT by refilling all the relevant paragraphs.
+
+;; You could do it a bit more efficiently (and robustly?) with just an
+;; auto-fill function, but that doesn't cope with changes other than
+;; through self-insertion. (Using auto-fill and after-change
+;; functions together didn't seem winning.) This could probably
+;; benefit from a less-general and faster `fill-paragraph-function',
+;; ideally as a primitive.
+
+;; The work is done in a local post-command hook but only if
+;; `refill-doit' has been set by the after-change function. Using
+;; `post-command-hooks' ensures simply that refilling only happens
+;; once per command.
+
+;; [Per Abrahamsen's maniac.el does a similar thing, but operates from
+;; post-command-hook. I don't understand the statement in it that
+;; after-change-hooks don't work for this purpose; perhaps there was
+;; some Emacs bug at the time. ISTR maniac has problems with
+;; whitespace at the end of paragraphs.]
+
+;;; Code:
+
+(defun refill-fill-paragraph (arg)
+ "Like `fill-paragraph' but don't delete whitespace at paragraph end."
+ ;; Should probably use a text property indicating previously-filled
+ ;; stuff to avoid filling before the point of change.
+ (let ((before (point)))
+ (save-excursion
+ (forward-paragraph)
+ (skip-syntax-backward "-")
+ (let ((end (point))
+ (beg (progn (backward-paragraph) (point))))
+ (goto-char before)
+ (save-restriction
+ (if use-hard-newlines
+ (fill-region beg end arg)
+ (fill-region-as-paragraph beg end arg)))))))
+
+(defvar refill-doit nil
+ "Non-nil means that `refill-post-command-function' does its processing.
+Set by `refill-after-change-function' in `after-change-hooks' and
+unset by `refill-post-command-function' in `post-command-hooks'. This
+ensures refilling is only done once per command that causes a change,
+regardless of the number of after-change calls from commands doing
+complex processing.")
+(make-variable-buffer-local 'refill-doit)
+
+(defun refill-after-change-function (beg end len)
+ "Function for `after-change-functions' which just sets `refill-doit'."
+ (unless undo-in-progress
+ (setq refill-doit t)))
+
+(defun refill-post-command-function ()
+ "Post-command function to do refilling (conditionally)."
+ (when refill-doit ; there was a change
+ ;; There's probably scope for more special cases here...
+ (cond
+ ((eq this-command 'self-insert-command)
+ ;; Respond to the same characters as auto-fill (other than
+ ;; newline, covered below).
+ (if (aref auto-fill-chars (char-before))
+ (refill-fill-paragraph nil)))
+ ((or (eq this-command 'quoted-insert)
+ (eq this-command 'fill-paragraph)
+ (eq this-command 'fill-region))
+ nil)
+ ((or (eq this-command 'newline)
+ (eq this-command 'newline-and-indent)
+ (eq this-command 'open-line))
+ ;; Don't zap what was just inserted.
+ (save-excursion
+ (beginning-of-line) ; for newline-and-indent
+ (skip-chars-backward "\n")
+ (save-restriction
+ (narrow-to-region (point-min) (point))
+ (refill-fill-paragraph nil)))
+ (widen)
+ (save-excursion
+ (skip-chars-forward "\n")
+ (save-restriction
+ (narrow-to-region (line-beginning-position) (point-max))
+ (refill-fill-paragraph nil))))
+ (t (refill-fill-paragraph nil)))
+ (setq refill-doit nil)))
+
+(defvar refill-mode nil
+ "Non-nil if Refill mode is active. Use `refill-mode' to toggle it.")
+(make-variable-buffer-local 'refill-mode)
+
+(defvar refill-mode-hook nil
+ "Normal hook run by function `refill-mode'.")
+
+(add-to-list 'minor-mode-alist '(refill-mode " Refill"))
+
+;;;###autoload
+(define-minor-mode refill-mode
+ "Toggle Refill minor mode.
+With prefix arg, turn Refill mode on iff arg is positive.
+
+When Refill mode is on, the current paragraph will be formatted when
+changes are made within it. Self-inserting characters only cause
+refilling if they would cause auto-filling."
+ nil " Refill" nil
+ ;; This provides the test for recursive paragraph filling.
+ (make-local-variable 'fill-paragraph-function)
+ (if refill-mode
+ (progn (add-hook (make-local-hook 'after-change-functions)
+ 'refill-after-change-function nil t)
+ (add-hook (make-local-hook 'post-command-hook)
+ 'refill-post-command-function nil t)
+ (set (make-local-variable 'fill-paragraph-function)
+ 'refill-fill-paragraph)
+ (auto-fill-mode 0))
+ (remove-hook 'after-change-functions 'refill-after-change-function t)
+ (remove-hook 'post-command-hook 'refill-post-command-function t)
+ (setq fill-paragraph-function nil)))
+
+(provide 'refill)
+
+;;; refill.el ends here
projects / emacs.git / commitdiff