1;;; refill.el --- `auto-fill' by refilling paragraphs on changes 2 3;; Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 4;; 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Dave Love <fx@gnu.org> 7;; Maintainer: Miles Bader <miles@gnu.org> 8;; Keywords: wp 9 10;; This file is part of GNU Emacs. 11 12;; GNU Emacs is free software; you can redistribute it and/or modify 13;; it under the terms of the GNU General Public License as published by 14;; the Free Software Foundation; either version 2, or (at your option) 15;; any later version. 16 17;; GNU Emacs is distributed in the hope that it will be useful, 18;; but WITHOUT ANY WARRANTY; without even the implied warranty of 19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20;; GNU General Public License for more details. 21 22;; You should have received a copy of the GNU General Public License 23;; along with GNU Emacs; see the file COPYING. If not, write to the 24;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 25;; Boston, MA 02110-1301, USA. 26 27;;; Commentary: 28 29;; Provides a mode where paragraphs are refilled after changes in them 30;; (using `after-change-functions'). This gives something akin to typical 31;; word processor-style filling. We restrict refilling due to 32;; self-insertion to the characters which trigger auto-fill. 33 34;; It partly satisfies a todo item in enriched.el for some value of 35;; `without slowing down editing too much'. It doesn't attempt to do 36;; anything (using `window-size-change-functions'?) about resizing 37;; windows -- who cares? 38 39;; This implementation is probably fragile and missing some special 40;; cases -- not extensively tested. Yanking paragraph breaks, for 41;; instance, won't DTRT by refilling all the relevant paragraphs. 42 43;; You could do it a bit more efficiently (and robustly?) with just an 44;; auto-fill function, but that doesn't cope with changes other than 45;; through self-insertion. (Using auto-fill and after-change 46;; functions together didn't seem winning.) This could probably 47;; benefit from a less-general and faster `fill-paragraph-function', 48;; ideally as a primitive. 49 50;; The work is done in a local post-command hook but only if 51;; `refill-doit' has been set by the after-change function. Using 52;; `post-command-hook' ensures simply that refilling only happens 53;; once per command. 54 55;; [Per Abrahamsen's maniac.el does a similar thing, but operates from 56;; post-command-hook. I don't understand the statement in it that 57;; after-change-functions don't work for this purpose; perhaps there was 58;; some Emacs bug at the time. ISTR maniac has problems with 59;; whitespace at the end of paragraphs.] 60 61;;; Todo/Bugs: 62 63;; - When deleting the first word on a line, the space after that word tends 64;; to become part of the fill-prefix, causing either wrong filling of the 65;; remaining text, or causing the cursor to move unexpectedly. Ex: 66;; Start with 67;; I>< blabla 68;; 69;; and hit backspace. We end up with 70;; 71;; ><blabla 72;; instead of 73;; >< blabla 74;; 75;; Other example. Start with 76;; 77;; Foo bar blablabla asdgf 78;; word>< asdfas dfasdfasd 79;; asd asdfa sdfasd sdf 80;; 81;; and hit M-backspace. We end up with 82;; 83;; Foo bar blablabla asdgf 84;; ><asdfas dfasdfasd asd 85;; asdfa sdfasd sdf 86 87;;; Code: 88 89(eval-when-compile (require 'cl)) 90 91(defgroup refill nil 92 "Refilling paragraphs on changes." 93 :group 'fill) 94 95(defvar refill-ignorable-overlay nil 96 "Portion of the most recently filled paragraph not needing filling. 97This is used to optimize refilling.") 98(make-variable-buffer-local 'refill-ignorable-overlay) 99 100(defun refill-adjust-ignorable-overlay (overlay afterp beg end &optional len) 101 "Adjust OVERLAY to not include the about-to-be-modified region." 102 (when (not afterp) 103 (save-excursion 104 (goto-char beg) 105 (forward-line -1) 106 (if (<= (point) (overlay-start overlay)) 107 ;; Just get OVERLAY out of the way 108 (move-overlay overlay (point-min) (point-min)) 109 ;; Make overlay contain only the region 110 (move-overlay overlay (overlay-start overlay) (point)))))) 111 112(defun refill-fill-paragraph-at (pos &optional arg) 113 "Like `fill-paragraph' at POS, but don't delete whitespace at paragraph end." 114 (save-excursion 115 (goto-char pos) 116 ;; FIXME: forward-paragraph seems to disregard `use-hard-newlines', 117 ;; leading to excessive refilling and wrong choice of fill-prefix. 118 ;; might be a bug in my paragraphs.el. 119 (forward-paragraph) 120 (skip-syntax-backward "-") 121 (let ((end (point)) 122 (beg (progn (backward-paragraph) (point))) 123 (obeg (overlay-start refill-ignorable-overlay)) 124 (oend (overlay-end refill-ignorable-overlay))) 125 (unless (> beg pos) ;Don't fill if point is outside the paragraph. 126 (goto-char pos) 127 (if (and (>= beg obeg) (< beg oend)) 128 ;; Limit filling to the modified tail of the paragraph. 129 (let ( ;; When adaptive-fill-mode is enabled, the filling 130 ;; functions will attempt to set the fill prefix from 131 ;; the fake paragraph bounds we pass in, so set it 132 ;; ourselves first, using the real paragraph bounds. 133 (fill-prefix 134 (if (and adaptive-fill-mode 135 (or (null fill-prefix) (string= fill-prefix ""))) 136 (fill-context-prefix beg end) 137 fill-prefix)) 138 ;; Turn off adaptive-fill-mode temporarily 139 (adaptive-fill-mode nil)) 140 (save-restriction 141 (if use-hard-newlines 142 (fill-region oend end arg) 143 (fill-region-as-paragraph oend end arg))) 144 (move-overlay refill-ignorable-overlay obeg (point))) 145 ;; Fill the whole paragraph 146 (save-restriction 147 (if use-hard-newlines 148 (fill-region beg end arg) 149 (fill-region-as-paragraph beg end arg))) 150 (move-overlay refill-ignorable-overlay beg (point))))))) 151 152(defun refill-fill-paragraph (arg) 153 "Like `fill-paragraph' but don't delete whitespace at paragraph end." 154 (refill-fill-paragraph-at (point) arg)) 155 156(defvar refill-doit nil 157 "Non-nil tells `refill-post-command-function' to do its processing. 158Set by `refill-after-change-function' in `after-change-functions' and 159unset by `refill-post-command-function' in `post-command-hook', and 160sometimes `refill-pre-command-function' in `pre-command-hook'. This 161ensures refilling is only done once per command that causes a change, 162regardless of the number of after-change calls from commands doing 163complex processing.") 164(make-variable-buffer-local 'refill-doit) 165 166(defun refill-after-change-function (beg end len) 167 "Function for `after-change-functions' which just sets `refill-doit'." 168 (unless undo-in-progress 169 (setq refill-doit end))) 170 171(defun refill-post-command-function () 172 "Post-command function to do refilling (conditionally)." 173 (when refill-doit ; there was a change 174 ;; There's probably scope for more special cases here... 175 (case this-command 176 (self-insert-command 177 ;; Treat self-insertion commands specially, since they don't 178 ;; always reset `refill-doit' -- for self-insertion commands that 179 ;; *don't* cause a refill, we want to leave it turned on so that 180 ;; any subsequent non-modification command will cause a refill. 181 (when (aref auto-fill-chars (char-before)) 182 ;; Respond to the same characters as auto-fill (other than 183 ;; newline, covered below). 184 (refill-fill-paragraph-at refill-doit) 185 (setq refill-doit nil))) 186 ((quoted-insert fill-paragraph fill-region) nil) 187 ((newline newline-and-indent open-line indent-new-comment-line 188 reindent-then-newline-and-indent) 189 ;; Don't zap what was just inserted. 190 (save-excursion 191 (beginning-of-line) ; for newline-and-indent 192 (skip-chars-backward "\n") 193 (save-restriction 194 (narrow-to-region (point-min) (point)) 195 (refill-fill-paragraph-at refill-doit))) 196 (widen) 197 (save-excursion 198 (skip-chars-forward "\n") 199 (save-restriction 200 (narrow-to-region (line-beginning-position) (point-max)) 201 (refill-fill-paragraph-at refill-doit)))) 202 (t 203 (refill-fill-paragraph-at refill-doit))) 204 (setq refill-doit nil))) 205 206(defun refill-pre-command-function () 207 "Pre-command function to do refilling (conditionally)." 208 (when (and refill-doit (not (eq this-command 'self-insert-command))) 209 ;; A previous setting of `refill-doit' didn't result in a refill, 210 ;; because it was a self-insert-command. Since the next command is 211 ;; something else, do the refill now. 212 (refill-fill-paragraph-at refill-doit) 213 (setq refill-doit nil))) 214 215(defvar refill-saved-state nil) 216 217;;;###autoload 218(define-minor-mode refill-mode 219 "Toggle Refill minor mode. 220With prefix arg, turn Refill mode on iff arg is positive. 221 222When Refill mode is on, the current paragraph will be formatted when 223changes are made within it. Self-inserting characters only cause 224refilling if they would cause auto-filling." 225 :group 'refill 226 :lighter " Refill" 227 :keymap '(("\177" . backward-delete-char-untabify)) 228 ;; Remove old state if necessary 229 (when refill-ignorable-overlay 230 (delete-overlay refill-ignorable-overlay) 231 (kill-local-variable 'refill-ignorable-overlay)) 232 (when (local-variable-p 'refill-saved-state) 233 (dolist (x refill-saved-state) 234 (set (make-local-variable (car x)) (cdr x))) 235 (kill-local-variable 'refill-saved-state)) 236 (if refill-mode 237 (progn 238 (add-hook 'after-change-functions 'refill-after-change-function nil t) 239 (add-hook 'post-command-hook 'refill-post-command-function nil t) 240 (add-hook 'pre-command-hook 'refill-pre-command-function nil t) 241 (set (make-local-variable 'refill-saved-state) 242 (mapcar (lambda (s) (cons s (symbol-value s))) 243 '(fill-paragraph-function auto-fill-function))) 244 ;; This provides the test for recursive paragraph filling. 245 (set (make-local-variable 'fill-paragraph-function) 246 'refill-fill-paragraph) 247 ;; When using justification, doing DEL on 2 spaces should remove 248 ;; both, otherwise, the subsequent refill will undo the DEL. 249 (set (make-local-variable 'backward-delete-char-untabify-method) 250 'hungry) 251 (setq refill-ignorable-overlay (make-overlay 1 1 nil nil t)) 252 (overlay-put refill-ignorable-overlay 'modification-hooks 253 '(refill-adjust-ignorable-overlay)) 254 (overlay-put refill-ignorable-overlay 'insert-behind-hooks 255 '(refill-adjust-ignorable-overlay)) 256 (auto-fill-mode 0)) 257 (remove-hook 'after-change-functions 'refill-after-change-function t) 258 (remove-hook 'post-command-hook 'refill-post-command-function t) 259 (kill-local-variable 'backward-delete-char-untabify-method))) 260 261(provide 'refill) 262 263;; arch-tag: 2c4ce9e8-1daa-4a3b-b6f8-fd6ac5bf6138 264;;; refill.el ends here 265