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1 | ;;; longlines.el --- automatically wrap long lines |
2 | ||
3 | ;; Copyright (C) 2000, 2001, 2004, 2005 by Free Software Foundation, Inc. | |
4 | ||
5 | ;; Authors: Kai Grossjohann <Kai.Grossjohann@CS.Uni-Dortmund.DE> | |
6 | ;; Alex Schroeder <alex@gnu.org> | |
7 | ;; Chong Yidong <cyd@stupidchicken.com> | |
8 | ;; Maintainer: Chong Yidong <cyd@stupidchicken.com> | |
9 | ;; Keywords: convenience | |
10 | ||
11 | ;; This file is part of GNU Emacs. | |
12 | ||
13 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
14 | ;; it under the terms of the GNU General Public License as published by | |
15 | ;; the Free Software Foundation; either version 2, or (at your option) | |
16 | ;; any later version. | |
17 | ||
18 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | ;; GNU General Public License for more details. | |
22 | ||
23 | ;; You should have received a copy of the GNU General Public License | |
24 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
25 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
26 | ;; Boston, MA 02111-1307, USA. | |
27 | ||
28 | ;;; Commentary: | |
29 | ||
30 | ;; Some text editors save text files with long lines, and they | |
31 | ;; automatically break these lines at whitespace, without actually | |
32 | ;; inserting any newline characters. When doing `M-q' in Emacs, you | |
33 | ;; are inserting newline characters. Longlines mode provides a file | |
34 | ;; format which wraps the long lines when reading a file and unwraps | |
35 | ;; the lines when saving the file. It can also wrap and unwrap | |
36 | ;; automatically as editing takes place. | |
37 | ||
38 | ;; Special thanks to Rod Smith for many useful bug reports. | |
39 | ||
40 | ;;; Code: | |
41 | ||
42 | (require 'easy-mmode) | |
43 | ||
44 | (defgroup longlines nil | |
45 | "Automatic wrapping of long lines when loading files." | |
46 | :group 'fill) | |
47 | ||
48 | (defcustom longlines-auto-wrap t | |
49 | "*Non-nil means long lines are automatically wrapped after each command. | |
50 | Otherwise, you can perform filling using `fill-paragraph' or | |
51 | `auto-fill-mode'. In any case, the soft newlines will be removed | |
52 | when the file is saved to disk." | |
53 | :group 'longlines | |
54 | :type 'boolean) | |
55 | ||
56 | (defcustom longlines-wrap-follows-window-size nil | |
57 | "*Non-nil means wrapping and filling happen at the edge of the window. | |
58 | Otherwise, `fill-column' is used, regardless of the window size. This | |
59 | does not work well when the buffer is displayed in multiple windows | |
60 | with differing widths." | |
61 | :group 'longlines | |
62 | :type 'boolean) | |
63 | ||
64 | (defcustom longlines-show-hard-newlines nil | |
65 | "*Non-nil means each hard newline is marked with a symbol. | |
66 | You can also enable the display temporarily, using the command | |
67 | `longlines-show-hard-newlines'" | |
68 | :group 'longlines | |
69 | :type 'boolean) | |
70 | ||
71 | (defcustom longlines-show-effect (propertize "|\n" 'face 'escape-glyph) | |
72 | "*A string to display when showing hard newlines. | |
73 | This is used when `longlines-show-hard-newlines' is on." | |
74 | :group 'longlines | |
75 | :type 'string) | |
76 | ||
77 | ;; Internal variables | |
78 | ||
79 | (defvar longlines-wrap-beg nil) | |
80 | (defvar longlines-wrap-end nil) | |
81 | (defvar longlines-wrap-point nil) | |
82 | (defvar longlines-showing nil) | |
83 | ||
84 | (make-variable-buffer-local 'longlines-wrap-beg) | |
85 | (make-variable-buffer-local 'longlines-wrap-end) | |
86 | (make-variable-buffer-local 'longlines-wrap-point) | |
87 | (make-variable-buffer-local 'longlines-showing) | |
88 | ||
89 | ;; Mode | |
90 | ||
91 | ;;;###autoload | |
92 | (define-minor-mode longlines-mode | |
93 | "Toggle Long Lines mode. | |
94 | In Long Lines mode, long lines are wrapped if they extend beyond | |
95 | `fill-column'. The soft newlines used for line wrapping will not | |
96 | show up when the text is yanked or saved to disk. | |
97 | ||
98 | If `longlines-auto-wrap' is non-nil, lines are automatically | |
99 | wrapped whenever the buffer is changed. You can always call | |
100 | `fill-paragraph' to fill individual paragraphs. | |
101 | ||
102 | If `longlines-show-hard-newlines' is non-nil, hard newlines will | |
103 | be marked by a symbol." | |
6da6c2fe | 104 | :group 'longlines :lighter " ll" |
cf6ffd8c RS |
105 | (if longlines-mode |
106 | ;; Turn on longlines mode | |
107 | (progn | |
108 | (use-hard-newlines 1 'never) | |
109 | (set (make-local-variable 'require-final-newline) nil) | |
110 | (add-to-list 'buffer-file-format 'longlines) | |
111 | (add-hook 'change-major-mode-hook 'longlines-mode-off nil t) | |
112 | (make-local-variable 'buffer-substring-filters) | |
113 | (add-to-list 'buffer-substring-filters 'longlines-encode-string) | |
114 | (when longlines-wrap-follows-window-size | |
115 | (set (make-local-variable 'fill-column) | |
116 | (- (window-width) window-min-width)) | |
117 | (add-hook 'window-configuration-change-hook | |
118 | 'longlines-window-change-function nil t)) | |
119 | (let ((buffer-undo-list t) | |
120 | (mod (buffer-modified-p))) | |
121 | ;; Turning off undo is OK since (spaces + newlines) is | |
122 | ;; conserved, except for a corner case in | |
123 | ;; longlines-wrap-lines that we'll never encounter from here | |
124 | (longlines-decode-region (point-min) (point-max)) | |
125 | (longlines-wrap-region (point-min) (point-max)) | |
126 | (set-buffer-modified-p mod)) | |
127 | (when (and longlines-show-hard-newlines | |
128 | (not longlines-showing)) | |
129 | (longlines-show-hard-newlines)) | |
130 | (when longlines-auto-wrap | |
131 | (auto-fill-mode 0) | |
132 | (add-hook 'after-change-functions | |
133 | 'longlines-after-change-function nil t) | |
134 | (add-hook 'post-command-hook | |
135 | 'longlines-post-command-function nil t))) | |
136 | ;; Turn off longlines mode | |
137 | (setq buffer-file-format (delete 'longlines buffer-file-format)) | |
138 | (if longlines-showing | |
139 | (longlines-unshow-hard-newlines)) | |
140 | (let ((buffer-undo-list t)) | |
141 | (longlines-encode-region (point-min) (point-max))) | |
142 | (remove-hook 'change-major-mode-hook 'longlines-mode-off t) | |
143 | (remove-hook 'before-kill-functions 'longlines-encode-region t) | |
144 | (remove-hook 'after-change-functions 'longlines-after-change-function t) | |
145 | (remove-hook 'post-command-hook 'longlines-post-command-function t) | |
146 | (remove-hook 'window-configuration-change-hook | |
147 | 'longlines-window-change-function t) | |
148 | (kill-local-variable 'fill-column))) | |
149 | ||
150 | (defun longlines-mode-off () | |
151 | "Turn off longlines mode. | |
152 | This function exists to be called by `change-major-mode-hook' when the | |
153 | major mode changes." | |
154 | (longlines-mode 0)) | |
155 | ||
156 | ;; Showing the effect of hard newlines in the buffer | |
157 | ||
158 | (defface longlines-visible-face | |
159 | '((t (:background "red"))) | |
160 | "Face used to make hard newlines visible in `longlines-mode'.") | |
161 | ||
162 | (defun longlines-show-hard-newlines (&optional arg) | |
163 | "Make hard newlines visible by adding a face. | |
164 | With optional argument ARG, make the hard newlines invisible again." | |
165 | (interactive "P") | |
166 | (let ((buffer-undo-list t) | |
167 | (mod (buffer-modified-p))) | |
168 | (if arg | |
169 | (longlines-unshow-hard-newlines) | |
170 | (setq longlines-showing t) | |
171 | (longlines-show-region (point-min) (point-max))) | |
172 | (set-buffer-modified-p mod))) | |
173 | ||
174 | (defun longlines-show-region (beg end) | |
175 | "Make hard newlines between BEG and END visible." | |
176 | (let* ((pmin (min beg end)) | |
177 | (pmax (max beg end)) | |
178 | (pos (text-property-any pmin pmax 'hard t))) | |
179 | (while pos | |
180 | (put-text-property pos (1+ pos) 'display | |
181 | (copy-sequence longlines-show-effect)) | |
182 | (setq pos (text-property-any (1+ pos) pmax 'hard t))))) | |
183 | ||
184 | (defun longlines-unshow-hard-newlines () | |
185 | "Make hard newlines invisible again." | |
186 | (interactive) | |
187 | (setq longlines-showing nil) | |
188 | (let ((pos (text-property-any (point-min) (point-max) 'hard t))) | |
189 | (while pos | |
190 | (remove-text-properties pos (1+ pos) '(display)) | |
191 | (setq pos (text-property-any (1+ pos) (point-max) 'hard t))))) | |
192 | ||
193 | ;; Wrapping the paragraphs. | |
194 | ||
195 | (defun longlines-wrap-region (beg end) | |
196 | "Wrap each successive line, starting with the line before BEG. | |
197 | Stop when we reach lines after END that don't need wrapping, or the | |
198 | end of the buffer." | |
199 | (setq longlines-wrap-point (point)) | |
200 | (goto-char beg) | |
201 | (forward-line -1) | |
202 | ;; Two successful longlines-wrap-line's in a row mean successive | |
203 | ;; lines don't need wrapping. | |
204 | (while (null (and (longlines-wrap-line) | |
205 | (or (eobp) | |
206 | (and (>= (point) end) | |
207 | (longlines-wrap-line)))))) | |
208 | (goto-char longlines-wrap-point)) | |
209 | ||
210 | (defun longlines-wrap-line () | |
211 | "If the current line needs to be wrapped, wrap it and return nil. | |
212 | If wrapping is performed, point remains on the line. If the line does | |
213 | not need to be wrapped, move point to the next line and return t." | |
214 | (if (longlines-set-breakpoint) | |
215 | (progn (backward-char 1) | |
216 | (delete-char 1) | |
217 | (insert-char ?\n 1) | |
218 | nil) | |
219 | (if (longlines-merge-lines-p) | |
220 | (progn (end-of-line) | |
221 | (delete-char 1) | |
222 | ;; After certain commands (e.g. kill-line), there may be two | |
223 | ;; successive soft newlines in the buffer. In this case, we | |
224 | ;; replace these two newlines by a single space. Unfortunately, | |
225 | ;; this breaks the conservation of (spaces + newlines), so we | |
226 | ;; have to fiddle with longlines-wrap-point. | |
227 | (if (or (bolp) (eolp)) | |
228 | (if (> longlines-wrap-point (point)) | |
229 | (setq longlines-wrap-point | |
230 | (1- longlines-wrap-point))) | |
231 | (insert-char ? 1)) | |
232 | nil) | |
233 | (forward-line 1) | |
234 | t))) | |
235 | ||
236 | (defun longlines-set-breakpoint () | |
237 | "Place point where we should break the current line, and return t. | |
238 | If the line should not be broken, return nil; point remains on the | |
239 | line." | |
240 | (move-to-column fill-column) | |
241 | (if (and (re-search-forward "[^ ]" (line-end-position) 1) | |
242 | (> (current-column) fill-column)) | |
243 | ;; This line is too long. Can we break it? | |
244 | (or (longlines-find-break-backward) | |
245 | (progn (move-to-column fill-column) | |
246 | (longlines-find-break-forward))))) | |
247 | ||
248 | (defun longlines-find-break-backward () | |
249 | "Move point backward to the first available breakpoint and return t. | |
250 | If no breakpoint is found, return nil." | |
251 | (and (search-backward " " (line-beginning-position) 1) | |
252 | (save-excursion | |
253 | (skip-chars-backward " " (line-beginning-position)) | |
254 | (null (bolp))) | |
255 | (progn (forward-char 1) | |
256 | (if (and fill-nobreak-predicate | |
257 | (run-hook-with-args-until-success | |
258 | 'fill-nobreak-predicate)) | |
259 | (progn (skip-chars-backward " " (line-beginning-position)) | |
260 | (longlines-find-break-backward)) | |
261 | t)))) | |
262 | ||
263 | (defun longlines-find-break-forward () | |
264 | "Move point forward to the first available breakpoint and return t. | |
265 | If no break point is found, return nil." | |
266 | (and (search-forward " " (line-end-position) 1) | |
267 | (progn (skip-chars-forward " " (line-end-position)) | |
268 | (null (eolp))) | |
269 | (if (and fill-nobreak-predicate | |
270 | (run-hook-with-args-until-success | |
271 | 'fill-nobreak-predicate)) | |
272 | (longlines-find-break-forward) | |
273 | t))) | |
274 | ||
275 | (defun longlines-merge-lines-p () | |
276 | "Return t if part of the next line can fit onto the current line. | |
277 | Otherwise, return nil. Text cannot be moved across hard newlines." | |
278 | (save-excursion | |
279 | (end-of-line) | |
280 | (and (null (eobp)) | |
281 | (null (get-text-property (point) 'hard)) | |
282 | (let ((space (- fill-column (current-column)))) | |
283 | (forward-line 1) | |
284 | (if (eq (char-after) ? ) | |
285 | t ; We can always merge some spaces | |
286 | (<= (if (search-forward " " (line-end-position) 1) | |
287 | (current-column) | |
288 | (1+ (current-column))) | |
289 | space)))))) | |
290 | ||
291 | (defun longlines-decode-region (beg end) | |
292 | "Turn all newlines between BEG and END into hard newlines." | |
293 | (save-excursion | |
294 | (goto-char (min beg end)) | |
295 | (while (search-forward "\n" (max beg end) t) | |
296 | (set-hard-newline-properties | |
297 | (match-beginning 0) (match-end 0))))) | |
298 | ||
299 | (defun longlines-encode-region (beg end &optional buffer) | |
300 | "Replace each soft newline between BEG and END with exactly one space. | |
301 | Hard newlines are left intact. The optional argument BUFFER exists for | |
302 | compatibility with `format-alist', and is ignored." | |
303 | (save-excursion | |
304 | (let ((mod (buffer-modified-p))) | |
305 | (goto-char (min beg end)) | |
306 | (while (search-forward "\n" (max (max beg end)) t) | |
307 | (unless (get-text-property (match-beginning 0) 'hard) | |
308 | (replace-match " "))) | |
309 | (set-buffer-modified-p mod) | |
310 | end))) | |
311 | ||
312 | (defun longlines-encode-string (string) | |
313 | "Return a copy of STRING with each soft newline replaced by a space. | |
314 | Hard newlines are left intact." | |
315 | (let* ((str (copy-sequence string)) | |
316 | (pos (string-match "\n" str))) | |
317 | (while pos | |
318 | (if (null (get-text-property pos 'hard str)) | |
319 | (aset str pos ? )) | |
320 | (setq pos (string-match "\n" str (1+ pos)))) | |
321 | str)) | |
322 | ||
323 | ;; Auto wrap | |
324 | ||
325 | (defun longlines-auto-wrap (&optional arg) | |
326 | "Turn on automatic line wrapping, and wrap the entire buffer. | |
327 | With optional argument ARG, turn off line wrapping." | |
328 | (interactive "P") | |
329 | (remove-hook 'after-change-functions 'longlines-after-change-function t) | |
330 | (remove-hook 'post-command-hook 'longlines-post-command-function t) | |
331 | (if arg | |
332 | (progn (setq longlines-auto-wrap nil) | |
333 | (message "Auto wrap disabled.")) | |
334 | (setq longlines-auto-wrap t) | |
335 | (add-hook 'after-change-functions | |
336 | 'longlines-after-change-function nil t) | |
337 | (add-hook 'post-command-hook | |
338 | 'longlines-post-command-function nil t) | |
339 | (let ((mod (buffer-modified-p))) | |
340 | (longlines-wrap-region (point-min) (point-max)) | |
341 | (set-buffer-modified-p mod)) | |
342 | (message "Auto wrap enabled."))) | |
343 | ||
344 | (defun longlines-after-change-function (beg end len) | |
345 | "Update `longlines-wrap-beg' and `longlines-wrap-end'. | |
346 | This is called by `after-change-functions' to keep track of the region | |
347 | that has changed." | |
348 | (unless undo-in-progress | |
349 | (setq longlines-wrap-beg | |
350 | (if longlines-wrap-beg (min longlines-wrap-beg beg) beg)) | |
351 | (setq longlines-wrap-end | |
352 | (if longlines-wrap-end (max longlines-wrap-end end) end)))) | |
353 | ||
354 | (defun longlines-post-command-function () | |
355 | "Perform line wrapping on the parts of the buffer that have changed. | |
356 | This is called by `post-command-hook' after each command." | |
357 | (when longlines-wrap-beg | |
358 | (cond ((or (eq this-command 'yank) | |
359 | (eq this-command 'yank-pop)) | |
360 | (longlines-decode-region (point) (mark t)) | |
361 | (if longlines-showing | |
362 | (longlines-show-region (point) (mark t)))) | |
363 | ((and (eq this-command 'newline) longlines-showing) | |
364 | (save-excursion | |
365 | (if (search-backward "\n" nil t) | |
366 | (longlines-show-region | |
367 | (match-beginning 0) (match-end 0)))))) | |
368 | (unless (or (eq this-command 'fill-paragraph) | |
369 | (eq this-command 'fill-region)) | |
370 | (longlines-wrap-region longlines-wrap-beg longlines-wrap-end)) | |
371 | (setq longlines-wrap-beg nil) | |
372 | (setq longlines-wrap-end nil))) | |
373 | ||
374 | (defun longlines-window-change-function () | |
375 | "Re-wrap the buffer if the window width has changed. | |
376 | This is called by `window-size-change-functions'." | |
377 | (when (/= fill-column (- (window-width) window-min-width)) | |
378 | (setq fill-column (- (window-width) window-min-width)) | |
379 | (let ((mod (buffer-modified-p))) | |
380 | (longlines-wrap-region (point-min) (point-max)) | |
381 | (set-buffer-modified-p mod)))) | |
382 | ||
383 | ;; Loading and saving | |
384 | ||
385 | (add-to-list | |
386 | 'format-alist | |
387 | (list 'longlines "Automatically wrap long lines." nil | |
388 | 'longlines-decode-region 'longlines-encode-region t nil)) | |
389 | ||
390 | (provide 'longlines) | |
391 | ||
96a29ab7 | 392 | ;; arch-tag: 3489d225-5506-47b9-8659-d8807b77c624 |
cf6ffd8c | 393 | ;;; longlines.el ends here |