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1 | ;;; refill.el --- `auto-fill' by refilling paragraphs on changes |
2 | ||
3 | ;; Copyright (C) 2000 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Author: Dave Love <fx@gnu.org> | |
6 | ;; Keywords: wp | |
7 | ||
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8 | ;; This file is part of GNU Emacs. |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
aaaf7be7 | 11 | ;; it under the terms of the GNU General Public License as published by |
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12 | ;; the Free Software Foundation; either version 2, or (at your option) |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
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16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
2be7dabc | 19 | |
aaaf7be7 | 20 | ;; You should have received a copy of the GNU General Public License |
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21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
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23 | ;; Boston, MA 02111-1307, USA. |
24 | ||
25 | ;;; Commentary: | |
26 | ||
27 | ;; Provides a mode where paragraphs are refilled after changes in them | |
7850e188 | 28 | ;; (using `after-change-functions'). This gives something akin to typical |
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29 | ;; word processor-style filling. We restrict refilling due to |
30 | ;; self-insertion to the characters which trigger auto-fill. | |
31 | ||
32 | ;; It partly satisfies a todo item in enriched.el for some value of | |
33 | ;; `without slowing down editing too much'. It doesn't attempt to do | |
34 | ;; anything (using `window-size-change-functions'?) about resizing | |
35 | ;; windows -- who cares? | |
36 | ||
37 | ;; This implementation is probably fragile and missing some special | |
38 | ;; cases -- not extensively tested. Yanking paragraph breaks, for | |
39 | ;; instance, won't DTRT by refilling all the relevant paragraphs. | |
40 | ||
41 | ;; You could do it a bit more efficiently (and robustly?) with just an | |
42 | ;; auto-fill function, but that doesn't cope with changes other than | |
43 | ;; through self-insertion. (Using auto-fill and after-change | |
44 | ;; functions together didn't seem winning.) This could probably | |
45 | ;; benefit from a less-general and faster `fill-paragraph-function', | |
46 | ;; ideally as a primitive. | |
47 | ||
48 | ;; The work is done in a local post-command hook but only if | |
49 | ;; `refill-doit' has been set by the after-change function. Using | |
7850e188 | 50 | ;; `post-command-hook' ensures simply that refilling only happens |
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51 | ;; once per command. |
52 | ||
53 | ;; [Per Abrahamsen's maniac.el does a similar thing, but operates from | |
54 | ;; post-command-hook. I don't understand the statement in it that | |
7850e188 | 55 | ;; after-change-functions don't work for this purpose; perhaps there was |
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56 | ;; some Emacs bug at the time. ISTR maniac has problems with |
57 | ;; whitespace at the end of paragraphs.] | |
58 | ||
59 | ;;; Code: | |
60 | ||
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61 | (defvar refill-ignorable-overlay nil |
62 | "Portion of the most recently filled paragraph not needing filling. | |
63 | This is used to optimize refilling.") | |
64 | (make-variable-buffer-local 'refill-ignorable-overlay) | |
65 | ||
66 | (defun refill-adjust-ignorable-overlay (overlay afterp beg end &optional len) | |
67 | "Adjust OVERLAY to not include the about-to-be-modified region." | |
68 | (when (not afterp) | |
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69 | (save-excursion |
70 | (goto-char beg) | |
71 | (forward-line -1) | |
72 | (if (<= (point) (overlay-start overlay)) | |
73 | ;; Just get OVERLAY out of the way | |
74 | (move-overlay overlay 1 1) | |
75 | ;; Make overlay contain only the region | |
76 | (move-overlay overlay (overlay-start overlay) (point)))))) | |
77 | ||
78 | (defun refill-fill-paragraph-at (pos &optional arg) | |
79 | "Like `fill-paragraph' at POS, but don't delete whitespace at paragraph end." | |
80 | (let (fill-pfx) | |
aaaf7be7 | 81 | (save-excursion |
867092e9 | 82 | (goto-char pos) |
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83 | (forward-paragraph) |
84 | (skip-syntax-backward "-") | |
85 | (let ((end (point)) | |
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86 | (beg (progn (backward-paragraph) (point))) |
87 | (obeg (overlay-start refill-ignorable-overlay)) | |
88 | (oend (overlay-end refill-ignorable-overlay))) | |
89 | (goto-char pos) | |
90 | (if (and (>= beg obeg) (< beg oend)) | |
91 | ;; Limit filling to the modified tail of the paragraph. | |
92 | (let (;; When adaptive-fill-mode is enabled, the filling | |
93 | ;; functions will attempt to set the fill prefix from | |
94 | ;; the fake paragraph bounds we pass in, so set it | |
95 | ;; ourselves first, using the real paragraph bounds. | |
96 | (fill-prefix | |
97 | (if (and adaptive-fill-mode | |
98 | (or (null fill-prefix) (string= fill-prefix ""))) | |
99 | (fill-context-prefix beg end) | |
100 | fill-prefix)) | |
101 | ;; Turn off adaptive-fill-mode temporarily | |
102 | (adaptive-fill-mode nil)) | |
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103 | (save-restriction |
104 | (if use-hard-newlines | |
105 | (fill-region oend end arg) | |
106 | (fill-region-as-paragraph oend end arg))) | |
107 | (setq fill-pfx fill-prefix) | |
108 | (move-overlay refill-ignorable-overlay obeg (point))) | |
109 | ;; Fill the whole paragraph | |
110 | (setq fill-pfx | |
111 | (save-restriction | |
112 | (if use-hard-newlines | |
113 | (fill-region beg end arg) | |
114 | (fill-region-as-paragraph beg end arg)))) | |
115 | (move-overlay refill-ignorable-overlay beg (point))))) | |
116 | (skip-line-prefix fill-pfx))) | |
117 | ||
118 | (defun refill-fill-paragraph (arg) | |
119 | "Like `fill-paragraph' but don't delete whitespace at paragraph end." | |
120 | (refill-fill-paragraph-at (point) arg)) | |
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121 | |
122 | (defvar refill-doit nil | |
123 | "Non-nil means that `refill-post-command-function' does its processing. | |
7850e188 | 124 | Set by `refill-after-change-function' in `after-change-functions' and |
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125 | unset by `refill-post-command-function' in `post-command-hook', and |
126 | sometimes `refill-pre-command-function' in `pre-command-hook'. This | |
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127 | ensures refilling is only done once per command that causes a change, |
128 | regardless of the number of after-change calls from commands doing | |
129 | complex processing.") | |
130 | (make-variable-buffer-local 'refill-doit) | |
131 | ||
132 | (defun refill-after-change-function (beg end len) | |
133 | "Function for `after-change-functions' which just sets `refill-doit'." | |
134 | (unless undo-in-progress | |
867092e9 | 135 | (setq refill-doit end))) |
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136 | |
137 | (defun refill-post-command-function () | |
138 | "Post-command function to do refilling (conditionally)." | |
867092e9 | 139 | (when refill-doit ; there was a change |
aaaf7be7 | 140 | ;; There's probably scope for more special cases here... |
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141 | (if (eq this-command 'self-insert-command) |
142 | ;; Treat self-insertion commands specially, since they don't | |
143 | ;; always reset `refill-doit' -- for self-insertion commands that | |
144 | ;; *don't* cause a refill, we want to leave it turned on so that | |
145 | ;; any subsequent non-modification command will cause a refill. | |
146 | (when (aref auto-fill-chars (char-before)) | |
147 | ;; Respond to the same characters as auto-fill (other than | |
148 | ;; newline, covered below). | |
149 | (refill-fill-paragraph-at refill-doit) | |
150 | (setq refill-doit nil)) | |
151 | (cond | |
152 | ((or (eq this-command 'quoted-insert) | |
153 | (eq this-command 'fill-paragraph) | |
154 | (eq this-command 'fill-region)) | |
155 | nil) | |
156 | ((or (eq this-command 'newline) | |
157 | (eq this-command 'newline-and-indent) | |
158 | (eq this-command 'open-line)) | |
159 | ;; Don't zap what was just inserted. | |
160 | (save-excursion | |
161 | (beginning-of-line) ; for newline-and-indent | |
162 | (skip-chars-backward "\n") | |
163 | (save-restriction | |
164 | (narrow-to-region (point-min) (point)) | |
165 | (refill-fill-paragraph-at refill-doit))) | |
166 | (widen) | |
167 | (save-excursion | |
168 | (skip-chars-forward "\n") | |
169 | (save-restriction | |
170 | (narrow-to-region (line-beginning-position) (point-max)) | |
171 | (refill-fill-paragraph-at refill-doit)))) | |
172 | (t | |
173 | (refill-fill-paragraph-at refill-doit))) | |
174 | (setq refill-doit nil)))) | |
175 | ||
176 | (defun refill-pre-command-function () | |
177 | "Pre-command function to do refilling (conditionally)." | |
178 | (when (and refill-doit (not (eq this-command 'self-insert-command))) | |
179 | ;; A previous setting of `refill-doit' didn't result in a refill, | |
180 | ;; because it was a self-insert-command. Since the next command is | |
181 | ;; something else, do the refill now. | |
182 | (refill-fill-paragraph-at refill-doit) | |
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183 | (setq refill-doit nil))) |
184 | ||
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185 | (defvar refill-late-fill-paragraph-function nil) |
186 | ||
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187 | ;;;###autoload |
188 | (define-minor-mode refill-mode | |
189 | "Toggle Refill minor mode. | |
190 | With prefix arg, turn Refill mode on iff arg is positive. | |
191 | ||
192 | When Refill mode is on, the current paragraph will be formatted when | |
193 | changes are made within it. Self-inserting characters only cause | |
194 | refilling if they would cause auto-filling." | |
195 | nil " Refill" nil | |
196 | ;; This provides the test for recursive paragraph filling. | |
197 | (make-local-variable 'fill-paragraph-function) | |
198 | (if refill-mode | |
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199 | (progn |
200 | (add-hook 'after-change-functions 'refill-after-change-function nil t) | |
201 | (add-hook 'post-command-hook 'refill-post-command-function nil t) | |
867092e9 | 202 | (add-hook 'pre-command-hook 'refill-pre-command-function nil t) |
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203 | (set (make-local-variable 'refill-late-fill-paragraph-function) |
204 | fill-paragraph-function) | |
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205 | (set (make-local-variable 'fill-paragraph-function) |
206 | 'refill-fill-paragraph) | |
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207 | (setq refill-ignorable-overlay (make-overlay 1 1 nil nil t)) |
208 | (overlay-put refill-ignorable-overlay 'modification-hooks | |
209 | '(refill-adjust-ignorable-overlay)) | |
210 | (overlay-put refill-ignorable-overlay 'insert-behind-hooks | |
211 | '(refill-adjust-ignorable-overlay)) | |
7850e188 | 212 | (auto-fill-mode 0)) |
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213 | (remove-hook 'after-change-functions 'refill-after-change-function t) |
214 | (remove-hook 'post-command-hook 'refill-post-command-function t) | |
867092e9 | 215 | (delete-overlay refill-ignorable-overlay) |
10ee3d79 | 216 | (setq fill-paragraph-function refill-late-fill-paragraph-function))) |
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217 | |
218 | (provide 'refill) | |
219 | ||
220 | ;;; refill.el ends here |