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1 | ;;; format.el -- read and save files in multiple formats |
2 | ;; Copyright (c) 1994 Free Software Foundation | |
3 | ||
4 | ;; Author: Boris Goldowsky <boris@cs.rochester.edu> | |
5 | ||
6 | ;; This file is part of GNU Emacs. | |
7 | ||
8 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
9 | ;; it under the terms of the GNU General Public License as published by | |
10 | ;; the Free Software Foundation; either version 2, or (at your option) | |
11 | ;; any later version. | |
12 | ;; | |
13 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
14 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | ;; GNU General Public License for more details. | |
17 | ;; | |
18 | ;; You should have received a copy of the GNU General Public License | |
19 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
20 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | ||
22 | ;;; Commentary: | |
23 | ;; This file defines a unified mechanism for saving & loading files stored in | |
24 | ;; different formats. `format-alist' contains information that directs | |
25 | ;; Emacs to call an encoding or decoding function when reading or writing | |
26 | ;; files that match certain conditions. | |
27 | ;; | |
28 | ;; When a file is visited, its format is determined by matching the beginning | |
29 | ;; of the file against regular expressions stored in `format-alist'. If this | |
30 | ;; fails, you can manually translate the buffer using `format-decode-buffer'. | |
31 | ;; In either case, the formats used are listed in the variable | |
32 | ;; `buffer-file-format', and become the default format for saving the buffer. | |
33 | ;; To save a buffer in a different format, change this variable, or use | |
34 | ;; `format-write-file'. | |
35 | ;; | |
36 | ;; Auto-save files are normally created in the same format as the visited | |
37 | ;; file, but the variable `auto-save-file-format' can be set to a particularly | |
38 | ;; fast or otherwise preferred format to be used for auto-saving (or nil to do | |
39 | ;; no encoding on auto-save files, but then you risk losing any | |
40 | ;; text-properties in the buffer). | |
41 | ;; | |
42 | ;; You can manually translate a buffer into or out of a particular format with | |
43 | ;; the functions `format-encode-buffer' and `format-decode-buffer'. | |
44 | ;; To translate just the region use the functions `format-encode-region' and | |
45 | ;; `format-decode-region'. | |
46 | ;; | |
47 | ;; You can define a new format by writing the encoding and decoding functions, | |
48 | ;; and adding an entry to `format-alist'. See enriched.el for an example of | |
49 | ;; how to implement a file format. There are various functions defined | |
50 | ;; in this file that may be useful for writing the encoding and decoding | |
51 | ;; functions: | |
52 | ;; * `format-annotate-region' and `format-deannotate-region' allow a single | |
53 | ;; alist of information to be used for encoding and decoding. The alist | |
54 | ;; defines a correspondence between strings in the file ("annotations") | |
55 | ;; and text-properties in the buffer. | |
56 | ;; * `format-replace-strings' is similarly useful for doing simple | |
57 | ;; string->string translations in a reversible manner. | |
58 | ||
59 | (put 'buffer-file-format 'permanent-local t) | |
60 | ||
61 | (defconst format-alist | |
62 | '((text/enriched "Extended MIME text/enriched format." | |
63 | "Content-[Tt]ype:[ \t]*text/enriched" | |
64 | enriched-decode enriched-encode t enriched-mode) | |
65 | (plain "Standard ASCII format, no text properties." | |
66 | ;; Plain only exists so that there is an obvious neutral choice in | |
67 | ;; the completion list. | |
68 | nil nil nil nil nil)) | |
69 | "List of information about understood file formats. | |
70 | Elements are of the form \(NAME DOC-STR REGEXP FROM-FN TO-FN MODIFY MODE-FN). | |
71 | NAME is a symbol, which is stored in `buffer-file-format'. | |
72 | DOC-STR should be a single line providing more information about the | |
73 | format. It is currently unused, but in the future will be shown to | |
74 | the user if they ask for more information. | |
75 | REGEXP is a regular expression to match against the beginning of the file; | |
76 | it should match only files in that format. | |
77 | FROM-FN is called to decode files in that format; it gets two args, BEGIN | |
78 | and END, and can make any modifications it likes, returning the new | |
79 | end. It must make sure that the beginning of the file no longer | |
80 | matches REGEXP, or else it will get called again. | |
81 | TO-FN is called to encode a region into that format; it is also passed BEGIN | |
82 | and END, and either returns a list of annotations like | |
83 | `write-region-annotate-functions', or modifies the region and returns | |
84 | the new end. | |
85 | MODIFY, if non-nil, means the TO-FN modifies the region. If nil, TO-FN may | |
86 | not make any changes and should return a list of annotations. | |
87 | MODE-FN, if specified, is called when visiting a file with that format.") | |
88 | ||
89 | ;;; Basic Functions (called from Lisp) | |
90 | ||
91 | (defun format-annotate-function (format from to) | |
92 | "Returns annotations for writing region as FORMAT. | |
93 | FORMAT is a symbol naming one of the formats defined in `format-alist', | |
94 | it must be a single symbol, not a list like `buffer-file-format'. | |
95 | This function works like a function on `write-region-annotate-functions': | |
96 | it either returns a list of annotations, or returns with a different buffer | |
97 | current, which contains the modified text to write. | |
98 | ||
99 | For most purposes, consider using `format-encode-region' instead." | |
100 | ;; This function is called by write-region (actually build-annotations) | |
101 | ;; for each element of buffer-file-format. | |
102 | (let* ((info (assq format format-alist)) | |
103 | (to-fn (nth 4 info)) | |
104 | (modify (nth 5 info))) | |
105 | (if to-fn | |
106 | (if modify | |
107 | ;; To-function wants to modify region. Copy to safe place. | |
108 | (let ((copy-buf (get-buffer-create " *Format Temp*"))) | |
109 | (copy-to-buffer copy-buf from to) | |
110 | (set-buffer copy-buf) | |
111 | (format-insert-annotations write-region-annotations-so-far from) | |
112 | (funcall to-fn (point-min) (point-max)) | |
113 | nil) | |
114 | ;; Otherwise just call function, it will return annotations. | |
115 | (funcall to-fn from to))))) | |
116 | ||
117 | (defun format-decode (format length &optional visit-flag) | |
118 | ;; This function is called by insert-file-contents whenever a file is read. | |
119 | "Decode text from any known FORMAT. | |
120 | FORMAT is a symbol appearing in `format-alist' or a list of such symbols, | |
121 | or nil, in which case this function tries to guess the format of the data by | |
122 | matching against the regular expressions in `format-alist'. After a match is | |
123 | found and the region decoded, the alist is searched again from the beginning | |
124 | for another match. | |
125 | ||
126 | Second arg LENGTH is the number of characters following point to operate on. | |
127 | If optional third arg VISIT-FLAG is true, set `buffer-file-format' | |
128 | to the list of formats used, and call any mode functions defined for those | |
129 | formats. | |
130 | ||
131 | Returns the new length of the decoded region. | |
132 | ||
133 | For most purposes, consider using `format-decode-region' instead." | |
134 | (let ((mod (buffer-modified-p)) | |
135 | (begin (point)) | |
136 | (end (+ (point) length))) | |
137 | (if (null format) | |
138 | ;; Figure out which format it is in, remember list in `format'. | |
139 | (let ((try format-alist)) | |
140 | (while try | |
141 | (let* ((f (car try)) | |
142 | (regexp (nth 2 f)) | |
143 | (p (point))) | |
144 | (if (and regexp (looking-at regexp) | |
145 | (< (match-end 0) (+ begin length))) | |
146 | (progn | |
147 | (setq format (cons (car f) format)) | |
148 | ;; Decode it | |
149 | (if (nth 3 f) (setq end (funcall (nth 3 f) begin end))) | |
150 | ;; Call visit function if required | |
151 | (if (and visit-flag (nth 6 f)) (funcall (nth 6 f) 1)) | |
152 | ;; Safeguard against either of the functions changing pt. | |
153 | (goto-char p) | |
154 | ;; Rewind list to look for another format | |
155 | (setq try format-alist)) | |
156 | (setq try (cdr try)))))) | |
157 | ;; Deal with given format(s) | |
158 | (or (listp format) (setq format (list format))) | |
159 | (let ((do format) f) | |
160 | (while do | |
161 | (or (setq f (assq (car do) format-alist)) | |
162 | (error "Unknown format" (car do))) | |
163 | ;; Decode: | |
164 | (if (nth 3 f) (setq end (funcall (nth 3 f) begin end))) | |
165 | ;; Call visit function if required | |
166 | (if (and visit-flag (nth 6 f)) (funcall (nth 6 f) 1)) | |
167 | (setq do (cdr do))))) | |
168 | (if visit-flag | |
169 | (setq buffer-file-format format)) | |
170 | (set-buffer-modified-p mod) | |
171 | ;; Return new length of region | |
172 | (- end begin))) | |
173 | ||
174 | ;;; | |
175 | ;;; Interactive functions & entry points | |
176 | ;;; | |
177 | ||
178 | (defun format-decode-buffer (&optional format) | |
179 | "Translate the buffer from some FORMAT. | |
180 | If the format is not specified, this function attempts to guess. | |
181 | `buffer-file-format' is set to the format used, and any mode-functions | |
182 | for the format are called." | |
183 | (interactive | |
184 | (list (format-read "Translate buffer from format (default: guess): "))) | |
185 | (save-excursion | |
186 | (goto-char (point-min)) | |
187 | (format-decode format (buffer-size) t))) | |
188 | ||
189 | (defun format-decode-region (from to &optional format) | |
190 | "Decode the region from some format. | |
191 | Arg FORMAT is optional; if omitted the format will be determined by looking | |
192 | for identifying regular expressions at the beginning of the region." | |
193 | (interactive | |
194 | (list (region-beginning) (region-end) | |
195 | (format-read "Translate region from format (default: guess): "))) | |
196 | (save-excursion | |
197 | (goto-char from) | |
198 | (format-decode format (- to from) nil))) | |
199 | ||
200 | (defun format-encode-buffer (&optional format) | |
201 | "Translate the buffer into FORMAT. | |
202 | FORMAT defaults to `buffer-file-format'. It is a symbol naming one of the | |
203 | formats defined in `format-alist', or a list of such symbols." | |
204 | (interactive | |
205 | (list (format-read (format "Translate buffer to format (default %s): " | |
206 | buffer-file-format)))) | |
207 | (format-encode-region (point-min) (point-max) format)) | |
208 | ||
209 | (defun format-encode-region (beg end &optional format) | |
210 | "Translate the region into some FORMAT. | |
211 | FORMAT defaults to `buffer-file-format', it is a symbol naming | |
212 | one of the formats defined in `format-alist', or a list of such symbols." | |
213 | (interactive | |
214 | (list (region-beginning) (region-end) | |
215 | (format-read (format "Translate region to format (default %s): " | |
216 | buffer-file-format)))) | |
217 | (if (null format) (setq format buffer-file-format)) | |
218 | (if (symbolp format) (setq format (list format))) | |
219 | (save-excursion | |
220 | (goto-char end) | |
221 | (let ((cur-buf (current-buffer)) | |
222 | (end (point-marker))) | |
223 | (while format | |
224 | (let* ((info (assq (car format) format-alist)) | |
225 | (to-fn (nth 4 info)) | |
226 | (modify (nth 5 info)) | |
227 | result) | |
228 | (if to-fn | |
229 | (if modify | |
230 | (setq end (funcall to-fn beg end)) | |
231 | (format-insert-annotations (funcall to-fn beg end)))) | |
232 | (setq format (cdr format))))))) | |
233 | ||
234 | (defun format-write-file (filename format) | |
235 | "Write current buffer into a FILE using some FORMAT. | |
236 | Makes buffer visit that file and sets the format as the default for future | |
237 | saves. If the buffer is already visiting a file, you can specify a directory | |
238 | name as FILE, to write a file of the same old name in that directory." | |
239 | (interactive | |
240 | ;; Same interactive spec as write-file, plus format question. | |
241 | (let* ((file (if buffer-file-name | |
242 | (read-file-name "Write file: " | |
243 | nil nil nil nil) | |
244 | (read-file-name "Write file: " | |
245 | (cdr (assq 'default-directory | |
246 | (buffer-local-variables))) | |
247 | nil nil (buffer-name)))) | |
248 | (fmt (format-read (format "Write file `%s' in format: " | |
249 | (file-name-nondirectory file))))) | |
250 | (list file fmt))) | |
251 | (setq buffer-file-format format) | |
252 | (write-file filename)) | |
253 | ||
254 | (defun format-read (&optional prompt) | |
255 | "Read and return the name of a format. | |
256 | Return value is a list, like `buffer-file-format'; it may be nil. | |
257 | Formats are defined in `format-alist'. Optional arg is the PROMPT to use." | |
258 | (let* ((table (mapcar (lambda (x) (list (symbol-name (car x)))) | |
259 | format-alist)) | |
260 | (ans (completing-read (or prompt "Format: ") table nil t))) | |
261 | (if (not (equal "" ans)) (list (intern ans))))) | |
262 | ||
263 | ||
264 | ;;; | |
265 | ;;; Below are some functions that may be useful in writing encoding and | |
266 | ;;; decoding functions for use in format-alist. | |
267 | ;;; | |
268 | ||
269 | (defun format-replace-strings (alist &optional reverse beg end) | |
270 | "Do multiple replacements on the buffer. | |
271 | ALIST is a list of (from . to) pairs, which should be proper arguments to | |
272 | `search-forward' and `replace-match' respectively. | |
273 | Optional 2nd arg REVERSE, if non-nil, means the pairs are (to . from), so that | |
274 | you can use the same list in both directions if it contains only literal | |
275 | strings. | |
276 | Optional args BEGIN and END specify a region of the buffer to operate on." | |
277 | (save-excursion | |
278 | (save-restriction | |
279 | (or beg (setq beg (point-min))) | |
280 | (if end (narrow-to-region (point-min) end)) | |
281 | (while alist | |
282 | (let ((from (if reverse (cdr (car alist)) (car (car alist)))) | |
283 | (to (if reverse (car (cdr alist)) (cdr (car alist))))) | |
284 | (goto-char beg) | |
285 | (while (search-forward from nil t) | |
286 | (goto-char (match-beginning 0)) | |
287 | (insert to) | |
288 | (set-text-properties (- (point) (length to)) (point) | |
289 | (text-properties-at (point))) | |
290 | (delete-region (point) (+ (point) (- (match-end 0) | |
291 | (match-beginning 0))))) | |
292 | (setq alist (cdr alist))))))) | |
293 | ||
294 | ;;; Some list-manipulation functions that we need. | |
295 | ||
296 | (defun format-delq-cons (cons list) | |
297 | "Remove the given CONS from LIST by side effect, | |
298 | and return the new LIST. Since CONS could be the first element | |
299 | of LIST, write `\(setq foo \(format-delq-cons element foo))' to be sure of | |
300 | changing the value of `foo'." | |
301 | (if (eq cons list) | |
302 | (cdr list) | |
303 | (let ((p list)) | |
304 | (while (not (eq (cdr p) cons)) | |
305 | (if (null p) (error "format-delq-cons: not an element.")) | |
306 | (setq p (cdr p))) | |
307 | ;; Now (cdr p) is the cons to delete | |
308 | (setcdr p (cdr cons)) | |
309 | list))) | |
310 | ||
311 | (defun format-make-relatively-unique (a b) | |
312 | "Delete common elements of lists A and B, return as pair. | |
313 | Compares using `equal'." | |
314 | (let* ((acopy (copy-sequence a)) | |
315 | (bcopy (copy-sequence b)) | |
316 | (tail acopy)) | |
317 | (while tail | |
318 | (let ((dup (member (car tail) bcopy)) | |
319 | (next (cdr tail))) | |
320 | (if dup (setq acopy (format-delq-cons tail acopy) | |
321 | bcopy (format-delq-cons dup bcopy))) | |
322 | (setq tail next))) | |
323 | (cons acopy bcopy))) | |
324 | ||
325 | (defun format-common-tail (a b) | |
326 | "Given two lists that have a common tail, return it. | |
327 | Compares with `equal', and returns the part of A that is equal to the | |
328 | equivalent part of B. If even the last items of the two are not equal, | |
329 | returns nil." | |
330 | (let ((la (length a)) | |
331 | (lb (length b))) | |
332 | ;; Make sure they are the same length | |
333 | (if (> la lb) | |
334 | (setq a (nthcdr (- la lb) a)) | |
335 | (setq b (nthcdr (- lb la) b)))) | |
336 | (while (not (equal a b)) | |
337 | (setq a (cdr a) | |
338 | b (cdr b))) | |
339 | a) | |
340 | ||
341 | (defun format-reorder (items order) | |
342 | "Arrange ITEMS to following partial ORDER. | |
343 | Elements of ITEMS equal to elements of ORDER will be rearranged to follow the | |
344 | ORDER. Unmatched items will go last." | |
345 | (if order | |
346 | (let ((item (member (car order) items))) | |
347 | (if item | |
348 | (cons (car item) | |
349 | (format-reorder (format-delq-cons item items) | |
350 | (cdr order))) | |
351 | (format-reorder items (cdr order)))) | |
352 | items)) | |
353 | ||
354 | (put 'face 'format-list-valued t) ; These text-properties take values | |
355 | (put 'unknown 'format-list-valued t) ; that are lists, the elements of which | |
356 | ; should be considered separately. | |
357 | ; See format-deannotate-region and | |
358 | ; format-annotate-region. | |
359 | ||
360 | ;;; | |
361 | ;;; Decoding | |
362 | ;;; | |
363 | ||
364 | (defun format-deannotate-region (from to translations next-fn) | |
365 | "Translate annotations in the region into text properties. | |
366 | This sets text properties between FROM to TO as directed by the | |
367 | TRANSLATIONS and NEXT-FN arguments. | |
368 | ||
369 | NEXT-FN is a function that searches forward from point for an annotation. | |
370 | It should return a list of 4 elements: \(BEGIN END NAME POSITIVE). BEGIN and | |
371 | END are buffer positions bounding the annotation, NAME is the name searched | |
372 | for in TRANSLATIONS, and POSITIVE should be non-nil if this annotation marks | |
373 | the beginning of a region with some property, or nil if it ends the region. | |
374 | NEXT-FN should return nil if there are no annotations after point. | |
375 | ||
376 | The basic format of the TRANSLATIONS argument is described in the | |
377 | documentation for the `format-annotate-region' function. There are some | |
378 | additional things to keep in mind for decoding, though: | |
379 | ||
380 | When an annotation is found, the TRANSLATIONS list is searched for a | |
381 | text-property name and value that corresponds to that annotation. If the | |
382 | text-property has several annotations associated with it, it will be used only | |
383 | if the other annotations are also in effect at that point. The first match | |
384 | found whose annotations are all present is used. | |
385 | ||
386 | The text property thus determined is set to the value over the region between | |
387 | the opening and closing annotations. However, if the text-property name has a | |
388 | non-nil `format-list-valued' property, then the value will be consed onto the | |
389 | surrounding value of the property, rather than replacing that value. | |
390 | ||
391 | There are some special symbols that can be used in the \"property\" slot of | |
392 | the TRANSLATIONS list: PARAMETER and FUNCTION \(spelled in uppercase). | |
393 | Annotations listed under the pseudo-property PARAMETER are considered to be | |
394 | arguments of the immediately surrounding annotation; the text between the | |
395 | opening and closing parameter annotations is deleted from the buffer but saved | |
396 | as a string. The surrounding annotation should be listed under the | |
397 | pseudo-property FUNCTION. Instead of inserting a text-property for this | |
398 | annotation, the function listed in the VALUE slot is called to make whatever | |
399 | changes are appropriate. The function's first two arguments are the START and | |
400 | END locations, and the rest of the arguments are any PARAMETERs found in that | |
401 | region. | |
402 | ||
403 | Any annotations that are found by NEXT-FN but not defined by TRANSLATIONS | |
404 | are saved as values of the `unknown' text-property \(which is list-valued). | |
405 | The TRANSLATIONS list should usually contain an entry of the form | |
406 | \(unknown \(nil format-annotate-value)) | |
407 | to write these unknown annotations back into the file." | |
408 | (save-excursion | |
409 | (save-restriction | |
410 | (narrow-to-region (point-min) to) | |
411 | (goto-char from) | |
412 | (let (next open-ans todo loc unknown-ans) | |
413 | (while (setq next (funcall next-fn)) | |
414 | (let* ((loc (nth 0 next)) | |
415 | (end (nth 1 next)) | |
416 | (name (nth 2 next)) | |
417 | (positive (nth 3 next)) | |
418 | (found nil)) | |
419 | ||
420 | ;; Delete the annotation | |
421 | (delete-region loc end) | |
422 | (if positive | |
423 | ;; Positive annotations are stacked, remembering location | |
424 | (setq open-ans (cons (list name loc) open-ans)) | |
425 | ;; It is a negative annotation: | |
426 | ;; Close the top annotation & add its text property. | |
427 | ;; If the file's nesting is messed up, the close might not match | |
428 | ;; the top thing on the open-annotations stack. | |
429 | ;; If no matching annotation is open, just ignore the close. | |
430 | (if (not (assoc name open-ans)) | |
431 | (message "Extra closing annotation (%s) in file" name) | |
432 | ;; If one is open, but not on the top of the stack, close | |
433 | ;; the things in between as well. Set `found' when the real | |
434 | ;; oneis closed. | |
435 | (while (not found) | |
436 | (let* ((top (car open-ans)) ; first on stack: should match. | |
437 | (top-name (car top)) | |
438 | (start (car (cdr top))) ; location of start | |
439 | (params (cdr (cdr top))) ; parameters | |
440 | (aalist translations) | |
441 | (matched nil)) | |
442 | (if (equal name top-name) | |
443 | (setq found t) | |
444 | (message "Improper nesting in file.")) | |
445 | ;; Look through property names in TRANSLATIONS | |
446 | (while aalist | |
447 | (let ((prop (car (car aalist))) | |
448 | (alist (cdr (car aalist)))) | |
449 | ;; And look through values for each property | |
450 | (while alist | |
451 | (let ((value (car (car alist))) | |
452 | (ans (cdr (car alist)))) | |
453 | (if (member top-name ans) | |
454 | ;; This annotation is listed, but still have to | |
455 | ;; check if multiple annotations are satisfied | |
456 | (if (member 'nil (mapcar | |
457 | (lambda (r) | |
458 | (assoc r open-ans)) | |
459 | ans)) | |
460 | nil ; multiple ans not satisfied | |
461 | ;; Yes, use the current property name & | |
462 | ;; value. Set loop variables to nil so loop | |
463 | ;; will exit. | |
464 | (setq alist nil aalist nil matched t | |
465 | ;; pop annotation off stack. | |
466 | open-ans (cdr open-ans)) | |
467 | (cond | |
468 | ;; Check for pseudo-properties | |
469 | ((eq prop 'PARAMETER) | |
470 | ;; This is a parameter of the top open ann: | |
471 | ;; delete text and use as arg. | |
472 | (if open-ans | |
473 | ;; (If nothing open, discard). | |
474 | (setq open-ans | |
475 | (cons (append (car open-ans) | |
476 | (list | |
477 | (buffer-substring | |
478 | start loc))) | |
479 | (cdr open-ans)))) | |
480 | (delete-region start loc)) | |
481 | ((eq prop 'FUNCTION) | |
482 | ;; Not a property, but a function to call. | |
483 | (let ((rtn (apply value start loc params))) | |
484 | (if rtn (setq todo (cons rtn todo))))) | |
485 | (t | |
486 | ;; Normal property/value pair | |
487 | (setq todo | |
488 | (cons (list start loc prop value) | |
489 | todo))))))) | |
490 | (setq alist (cdr alist)))) | |
491 | (setq aalist (cdr aalist))) | |
492 | (if matched | |
493 | nil | |
494 | ;; Didn't find any match for the annotation: | |
495 | ;; Store as value of text-property `unknown'. | |
496 | (setq open-ans (cdr open-ans)) | |
497 | (setq todo (cons (list start loc 'unknown top-name) | |
498 | todo)) | |
499 | (setq unknown-ans (cons name unknown-ans))))))))) | |
500 | ||
501 | ;; Once entire file has been scanned, add the properties. | |
502 | (while todo | |
503 | (let* ((item (car todo)) | |
504 | (from (nth 0 item)) | |
505 | (to (nth 1 item)) | |
506 | (prop (nth 2 item)) | |
507 | (val (nth 3 item))) | |
508 | ||
509 | (put-text-property | |
510 | from to prop | |
511 | (cond ((numberp val) ; add to ambient value if numeric | |
512 | (+ val (or (get-text-property from prop) 0))) | |
513 | ((get prop 'format-list-valued) ; value gets consed onto | |
514 | ; list-valued properties | |
515 | (let ((prev (get-text-property from prop))) | |
516 | (cons val (if (listp prev) prev (list prev))))) | |
517 | (t val)))) ; normally, just set to val. | |
518 | (setq todo (cdr todo))) | |
519 | ||
520 | (if unknown-ans | |
521 | (message "Unknown annotations: %s" unknown-ans)))))) | |
522 | ||
523 | ;;; | |
524 | ;;; Encoding | |
525 | ;;; | |
526 | ||
527 | (defun format-insert-annotations (list &optional offset) | |
528 | "Apply list of annotations to buffer as `write-region' would. | |
529 | Inserts each element of the given LIST of buffer annotations at its | |
530 | appropriate place. Use second arg OFFSET if the annotations' locations are | |
531 | not relative to the beginning of the buffer: annotations will be inserted | |
532 | at their location-OFFSET+1 \(ie, the offset is treated as the character number | |
533 | of the first character in the buffer)." | |
534 | (if (not offset) | |
535 | (setq offset 0) | |
536 | (setq offset (1- offset))) | |
537 | (let ((l (reverse list))) | |
538 | (while l | |
539 | (goto-char (- (car (car l)) offset)) | |
540 | (insert (cdr (car l))) | |
541 | (setq l (cdr l))))) | |
542 | ||
543 | (defun format-annotate-value (old new) | |
544 | "Return OLD and NEW as a \(close . open) annotation pair. | |
545 | Useful as a default function for TRANSLATIONS alist when the value of the text | |
546 | property is the name of the annotation that you want to use, as it is for the | |
547 | `unknown' text property." | |
548 | (cons (if old (list old)) | |
549 | (if new (list new)))) | |
550 | ||
551 | (defun format-annotate-region (from to trans format-fn ignore) | |
552 | "Generate annotations for text properties in the region. | |
553 | Searches for changes between FROM and TO, and describes them with a list of | |
554 | annotations as defined by alist TRANSLATIONS and FORMAT-FN. IGNORE lists text | |
555 | properties not to consider; any text properties that are neither ignored nor | |
556 | listed in TRANSLATIONS are warned about. | |
557 | If you actually want to modify the region, give the return value of this | |
558 | function to `format-insert-annotations'. | |
559 | ||
560 | Format of the TRANSLATIONS argument: | |
561 | ||
562 | Each element is a list whose car is a PROPERTY, and the following | |
563 | elements are VALUES of that property followed by the names of zero or more | |
564 | ANNOTATIONS. Whenever the property takes on that value, the annotations | |
565 | \(as formatted by FORMAT-FN) are inserted into the file. | |
566 | When the property stops having that value, the matching negated annotation | |
567 | will be inserted \(it may actually be closed earlier and reopened, if | |
568 | necessary, to keep proper nesting). | |
569 | ||
570 | If the property's value is a list, then each element of the list is dealt with | |
571 | separately. | |
572 | ||
573 | If a VALUE is numeric, then it is assumed that there is a single annotation | |
574 | and each occurrence of it increments the value of the property by that number. | |
575 | Thus, given the entry \(left-margin \(4 \"indent\")), if the left margin | |
576 | changes from 4 to 12, two <indent> annotations will be generated. | |
577 | ||
578 | If the VALUE is nil, then instead of annotations, a function should be | |
579 | specified. This function is used as a default: it is called for all | |
580 | transitions not explicitly listed in the table. The function is called with | |
581 | two arguments, the OLD and NEW values of the property. It should return | |
582 | lists of annotations like `format-annotate-location' does. | |
583 | ||
584 | The same structure can be used in reverse for reading files." | |
585 | (let ((all-ans nil) ; All annotations - becomes return value | |
586 | (open-ans nil) ; Annotations not yet closed | |
587 | (loc nil) ; Current location | |
588 | (not-found nil)) ; Properties that couldn't be saved | |
589 | (while (or (null loc) | |
590 | (and (setq loc (next-property-change loc nil to)) | |
591 | (< loc to))) | |
592 | (or loc (setq loc from)) | |
593 | (let* ((ans (format-annotate-location loc (= loc from) ignore trans)) | |
594 | (neg-ans (format-reorder (aref ans 0) open-ans)) | |
595 | (pos-ans (aref ans 1)) | |
596 | (ignored (aref ans 2))) | |
597 | (setq not-found (append ignored not-found) | |
598 | ignore (append ignored ignore)) | |
599 | ;; First do the negative (closing) annotations | |
600 | (while neg-ans | |
601 | ;; Check if it's missing. This can happen (eg, a numeric property | |
602 | ;; going negative can generate closing annotations before there are | |
603 | ;; any open). Warn user & ignore. | |
604 | (if (not (member (car neg-ans) open-ans)) | |
605 | (message "Can't close %s: not open." (car neg-ans)) | |
606 | (while (not (equal (car neg-ans) (car open-ans))) | |
607 | ;; To close anno. N, need to first close ans 1 to N-1, | |
608 | ;; remembering to re-open them later. | |
609 | (setq pos-ans (cons (car open-ans) pos-ans)) | |
610 | (setq all-ans | |
611 | (cons (cons loc (funcall format-fn (car open-ans) nil)) | |
612 | all-ans)) | |
613 | (setq open-ans (cdr open-ans))) | |
614 | ;; Now remove the one we're really interested in from open list. | |
615 | (setq open-ans (cdr open-ans)) | |
616 | ;; And put the closing annotation here. | |
617 | (setq all-ans | |
618 | (cons (cons loc (funcall format-fn (car neg-ans) nil)) | |
619 | all-ans))) | |
620 | (setq neg-ans (cdr neg-ans))) | |
621 | ;; Now deal with positive (opening) annotations | |
622 | (let ((p pos-ans)) | |
623 | (while pos-ans | |
624 | (setq open-ans (cons (car pos-ans) open-ans)) | |
625 | (setq all-ans | |
626 | (cons (cons loc (funcall format-fn (car pos-ans) t)) | |
627 | all-ans)) | |
628 | (setq pos-ans (cdr pos-ans)))))) | |
629 | ||
630 | ;; Close any annotations still open | |
631 | (while open-ans | |
632 | (setq all-ans | |
633 | (cons (cons to (funcall format-fn (car open-ans) nil)) | |
634 | all-ans)) | |
635 | (setq open-ans (cdr open-ans))) | |
636 | (if not-found | |
637 | (message "These text properties could not be saved:\n %s" | |
638 | not-found)) | |
639 | (nreverse all-ans))) | |
640 | ||
641 | ;;; Internal functions for format-annotate-region. | |
642 | ||
643 | (defun format-annotate-location (loc all ignore trans) | |
644 | "Return annotation(s) needed at LOCATION. | |
645 | This includes any properties that change between LOC-1 and LOC. | |
646 | If ALL is true, don't look at previous location, but generate annotations for | |
647 | all non-nil properties. | |
648 | Third argument IGNORE is a list of text-properties not to consider. | |
649 | ||
650 | Return value is a vector of 3 elements: | |
651 | 1. List of names of the annotations to close | |
652 | 2. List of the names of annotations to open. | |
653 | 3. List of properties that were ignored or couldn't be annotated." | |
654 | (let* ((prev-loc (1- loc)) | |
655 | (before-plist (if all nil (text-properties-at prev-loc))) | |
656 | (after-plist (text-properties-at loc)) | |
657 | p negatives positives prop props not-found) | |
658 | ;; make list of all property names involved | |
659 | (setq p before-plist) | |
660 | (while p | |
661 | (if (not (memq (car p) props)) | |
662 | (setq props (cons (car p) props))) | |
663 | (setq p (cdr (cdr p)))) | |
664 | (setq p after-plist) | |
665 | (while p | |
666 | (if (not (memq (car p) props)) | |
667 | (setq props (cons (car p) props))) | |
668 | (setq p (cdr (cdr p)))) | |
669 | ||
670 | (while props | |
671 | (setq prop (car props) | |
672 | props (cdr props)) | |
673 | (if (memq prop ignore) | |
674 | nil ; If it's been ignored before, ignore it now. | |
675 | (let ((before (if all nil (car (cdr (memq prop before-plist))))) | |
676 | (after (car (cdr (memq prop after-plist))))) | |
677 | (if (equal before after) | |
678 | nil ; no change; ignore | |
679 | (let ((result (format-annotate-single-property-change | |
680 | prop before after trans))) | |
681 | (if (not result) | |
682 | (setq not-found (cons prop not-found)) | |
683 | (setq negatives (nconc negatives (car result)) | |
684 | positives (nconc positives (cdr result))))))))) | |
685 | (vector negatives positives not-found))) | |
686 | ||
687 | (defun format-annotate-single-property-change (prop old new trans) | |
688 | "Return annotations for PROPERTY changing from OLD to NEW. | |
689 | These are searched for in the TRANSLATIONS alist. | |
690 | If NEW does not appear in the list, but there is a default function, then that | |
691 | function is called. | |
692 | Annotations to open and to close are returned as a dotted pair." | |
693 | (let ((prop-alist (cdr (assoc prop trans))) | |
694 | default) | |
695 | (if (not prop-alist) | |
696 | nil | |
697 | ;; If property is numeric, nil means 0 | |
698 | (cond ((and (numberp old) (null new)) | |
699 | (setq new 0)) | |
700 | ((and (numberp new) (null old)) | |
701 | (setq old 0))) | |
702 | ;; If either old or new is a list, have to treat both that way. | |
703 | (if (or (consp old) (consp new)) | |
704 | (let* ((old (if (listp old) old (list old))) | |
705 | (new (if (listp new) new (list new))) | |
706 | (tail (format-common-tail old new)) | |
707 | close open) | |
708 | (while old | |
709 | (setq close | |
710 | (append (car (format-annotate-atomic-property-change | |
711 | prop-alist (car old) nil)) | |
712 | close) | |
713 | old (cdr old))) | |
714 | (while new | |
715 | (setq open | |
716 | (append (cdr (format-annotate-atomic-property-change | |
717 | prop-alist nil (car new))) | |
718 | open) | |
719 | new (cdr new))) | |
720 | (format-make-relatively-unique close open)) | |
721 | (format-annotate-atomic-property-change prop-alist old new))))) | |
722 | ||
723 | (defun format-annotate-atomic-property-change (prop-alist old new) | |
724 | "Internal function annotate a single property change. | |
725 | PROP-ALIST is the relevant segement of a TRANSLATIONS list. | |
726 | OLD and NEW are the values." | |
727 | (cond | |
728 | ;; Numerical annotation - use difference | |
729 | ((and (numberp old) (numberp new)) | |
730 | (let* ((entry (progn | |
731 | (while (and (car (car prop-alist)) | |
732 | (not (numberp (car (car prop-alist))))) | |
733 | (setq prop-alist (cdr prop-alist))) | |
734 | (car prop-alist))) | |
735 | (increment (car (car prop-alist))) | |
736 | (n (ceiling (/ (float (- new old)) (float increment)))) | |
737 | (anno (car (cdr (car prop-alist))))) | |
738 | (if (> n 0) | |
739 | (cons nil (make-list n anno)) | |
740 | (cons (make-list (- n) anno) nil)))) | |
741 | ||
742 | ;; Standard annotation | |
743 | (t (let ((close (and old (cdr (assoc old prop-alist)))) | |
744 | (open (and new (cdr (assoc new prop-alist))))) | |
745 | (if (or close open) | |
746 | (format-make-relatively-unique close open) | |
747 | ;; Call "Default" function, if any | |
748 | (let ((default (assq nil prop-alist))) | |
749 | (if default | |
750 | (funcall (car (cdr default)) old new)))))))) | |
751 | ||
752 | ;; format.el ends here |