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30764597 | 1 | ;;; syntax.el --- helper functions to find syntactic context |
88a05faf | 2 | |
73b0cd50 | 3 | ;; Copyright (C) 2000-2011 Free Software Foundation, Inc. |
88a05faf | 4 | |
30764597 PJ |
5 | ;; Maintainer: FSF |
6 | ;; Keywords: internal | |
7 | ||
88a05faf SM |
8 | ;; This file is part of GNU Emacs. |
9 | ||
d6cba7ae | 10 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
88a05faf | 11 | ;; it under the terms of the GNU General Public License as published by |
d6cba7ae GM |
12 | ;; the Free Software Foundation, either version 3 of the License, or |
13 | ;; (at your option) any later version. | |
88a05faf SM |
14 | |
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
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. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
d6cba7ae | 21 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
88a05faf SM |
22 | |
23 | ;;; Commentary: | |
24 | ||
25 | ;; The main exported function is `syntax-ppss'. You might also need | |
9c5b2653 | 26 | ;; to call `syntax-ppss-flush-cache' or to add it to |
ad8a840d | 27 | ;; before-change-functions'(although this is automatically done by |
88a05faf | 28 | ;; syntax-ppss when needed, but that might fail if syntax-ppss is |
ad8a840d | 29 | ;; called in a context where before-change-functions is temporarily |
88a05faf SM |
30 | ;; let-bound to nil). |
31 | ||
32 | ;;; Todo: | |
33 | ||
34 | ;; - do something about the case where the syntax-table is changed. | |
35 | ;; This typically happens with tex-mode and its `$' operator. | |
88a05faf SM |
36 | ;; - new functions `syntax-state', ... to replace uses of parse-partial-state |
37 | ;; with something higher-level (similar to syntax-ppss-context). | |
38 | ;; - interaction with mmm-mode. | |
88a05faf SM |
39 | |
40 | ;;; Code: | |
41 | ||
42 | ;; Note: PPSS stands for `parse-partial-sexp state' | |
43 | ||
44 | (eval-when-compile (require 'cl)) | |
45 | ||
746dca00 JB |
46 | (defvar font-lock-beginning-of-syntax-function) |
47 | ||
cf38dd42 SM |
48 | ;;; Applying syntax-table properties where needed. |
49 | ||
50 | (defvar syntax-propertize-function nil | |
51 | ;; Rather than a -functions hook, this is a -function because it's easier | |
52 | ;; to do a single scan than several scans: with multiple scans, one cannot | |
53 | ;; assume that the text before point has been propertized, so syntax-ppss | |
54 | ;; gives unreliable results (and stores them in its cache to boot, so we'd | |
55 | ;; have to flush that cache between each function, and we couldn't use | |
56 | ;; syntax-ppss-flush-cache since that would not only flush the cache but also | |
57 | ;; reset syntax-propertize--done which should not be done in this case). | |
58 | "Mode-specific function to apply the syntax-table properties. | |
b879a6e2 SM |
59 | Called with 2 arguments: START and END. |
60 | This function can call `syntax-ppss' on any position before END, but it | |
61 | should not call `syntax-ppss-flush-cache', which means that it should not | |
62 | call `syntax-ppss' on some position and later modify the buffer on some | |
63 | earlier position.") | |
cf38dd42 SM |
64 | |
65 | (defvar syntax-propertize-chunk-size 500) | |
66 | ||
67 | (defvar syntax-propertize-extend-region-functions | |
68 | '(syntax-propertize-wholelines) | |
69 | "Special hook run just before proceeding to propertize a region. | |
70 | This is used to allow major modes to help `syntax-propertize' find safe buffer | |
71 | positions as beginning and end of the propertized region. Its most common use | |
72 | is to solve the problem of /identification/ of multiline elements by providing | |
73 | a function that tries to find such elements and move the boundaries such that | |
74 | they do not fall in the middle of one. | |
75 | Each function is called with two arguments (START and END) and it should return | |
76 | either a cons (NEW-START . NEW-END) or nil if no adjustment should be made. | |
77 | These functions are run in turn repeatedly until they all return nil. | |
78 | Put first the functions more likely to cause a change and cheaper to compute.") | |
79 | ;; Mark it as a special hook which doesn't use any global setting | |
80 | ;; (i.e. doesn't obey the element t in the buffer-local value). | |
81 | (make-variable-buffer-local 'syntax-propertize-extend-region-functions) | |
82 | ||
83 | (defun syntax-propertize-wholelines (start end) | |
84 | (goto-char start) | |
85 | (cons (line-beginning-position) | |
86 | (progn (goto-char end) | |
87 | (if (bolp) (point) (line-beginning-position 2))))) | |
88 | ||
89 | (defun syntax-propertize-multiline (beg end) | |
90 | "Let `syntax-propertize' pay attention to the syntax-multiline property." | |
91 | (when (and (> beg (point-min)) | |
92 | (get-text-property (1- beg) 'syntax-multiline)) | |
93 | (setq beg (or (previous-single-property-change beg 'syntax-multiline) | |
94 | (point-min)))) | |
95 | ;; | |
96 | (when (get-text-property end 'font-lock-multiline) | |
97 | (setq end (or (text-property-any end (point-max) | |
98 | 'syntax-multiline nil) | |
99 | (point-max)))) | |
100 | (cons beg end)) | |
101 | ||
102 | (defvar syntax-propertize--done -1 | |
103 | "Position upto which syntax-table properties have been set.") | |
104 | (make-variable-buffer-local 'syntax-propertize--done) | |
105 | ||
106 | (defun syntax-propertize--shift-groups (re n) | |
107 | (replace-regexp-in-string | |
108 | "\\\\(\\?\\([0-9]+\\):" | |
109 | (lambda (s) | |
110 | (replace-match | |
111 | (number-to-string (+ n (string-to-number (match-string 1 s)))) | |
112 | t t s 1)) | |
113 | re t t)) | |
114 | ||
b879a6e2 SM |
115 | (defmacro syntax-propertize-precompile-rules (&rest rules) |
116 | "Return a precompiled form of RULES to pass to `syntax-propertize-rules'. | |
117 | The arg RULES can be of the same form as in `syntax-propertize-rules'. | |
118 | The return value is an object that can be passed as a rule to | |
119 | `syntax-propertize-rules'. | |
120 | I.e. this is useful only when you want to share rules among several | |
121 | syntax-propertize-functions." | |
122 | (declare (debug syntax-propertize-rules)) | |
123 | ;; Precompile? Yeah, right! | |
124 | ;; Seriously, tho, this is a macro for 2 reasons: | |
125 | ;; - we could indeed do some pre-compilation at some point in the future, | |
126 | ;; e.g. fi/when we switch to a DFA-based implementation of | |
127 | ;; syntax-propertize-rules. | |
128 | ;; - this lets Edebug properly annotate the expressions inside RULES. | |
129 | `',rules) | |
130 | ||
cf38dd42 SM |
131 | (defmacro syntax-propertize-rules (&rest rules) |
132 | "Make a function that applies RULES for use in `syntax-propertize-function'. | |
133 | The function will scan the buffer, applying the rules where they match. | |
134 | The buffer is scanned a single time, like \"lex\" would, rather than once | |
135 | per rule. | |
136 | ||
b879a6e2 SM |
137 | Each RULE can be a symbol, in which case that symbol's value should be, |
138 | at macro-expansion time, a precompiled set of rules, as returned | |
139 | by `syntax-propertize-precompile-rules'. | |
140 | ||
141 | Otherwise, RULE should have the form (REGEXP HIGHLIGHT1 ... HIGHLIGHTn), where | |
142 | REGEXP is an expression (evaluated at time of macro-expansion) that returns | |
143 | a regexp, and where HIGHLIGHTs have the form (NUMBER SYNTAX) which means to | |
cf38dd42 SM |
144 | apply the property SYNTAX to the chars matched by the subgroup NUMBER |
145 | of the regular expression, if NUMBER did match. | |
146 | SYNTAX is an expression that returns a value to apply as `syntax-table' | |
147 | property. Some expressions are handled specially: | |
148 | - if SYNTAX is a string, then it is converted with `string-to-syntax'; | |
149 | - if SYNTAX has the form (prog1 EXP . EXPS) then the value returned by EXP | |
150 | will be applied to the buffer before running EXPS and if EXP is a string it | |
151 | is also converted with `string-to-syntax'. | |
152 | The SYNTAX expression is responsible to save the `match-data' if needed | |
153 | for subsequent HIGHLIGHTs. | |
154 | Also SYNTAX is free to move point, in which case RULES may not be applied to | |
155 | some parts of the text or may be applied several times to other parts. | |
156 | ||
157 | Note: back-references in REGEXPs do not work." | |
b879a6e2 SM |
158 | (declare (debug (&rest &or symbolp ;FIXME: edebug this eval step. |
159 | (form &rest | |
cf38dd42 | 160 | (numberp |
b879a6e2 | 161 | [&or stringp ;FIXME: Use &wrap |
cf38dd42 SM |
162 | ("prog1" [&or stringp def-form] def-body) |
163 | def-form]))))) | |
b879a6e2 SM |
164 | (let ((newrules nil)) |
165 | (while rules | |
166 | (if (symbolp (car rules)) | |
167 | (setq rules (append (symbol-value (pop rules)) rules)) | |
168 | (push (pop rules) newrules))) | |
169 | (setq rules (nreverse newrules))) | |
cf38dd42 SM |
170 | (let* ((offset 0) |
171 | (branches '()) | |
172 | ;; We'd like to use a real DFA-based lexer, usually, but since Emacs | |
173 | ;; doesn't have one yet, we fallback on building one large regexp | |
174 | ;; and use groups to determine which branch of the regexp matched. | |
175 | (re | |
176 | (mapconcat | |
177 | (lambda (rule) | |
b879a6e2 SM |
178 | (let* ((orig-re (eval (car rule))) |
179 | (re orig-re)) | |
cf38dd42 SM |
180 | (when (and (assq 0 rule) (cdr rules)) |
181 | ;; If there's more than 1 rule, and the rule want to apply | |
182 | ;; highlight to match 0, create an extra group to be able to | |
183 | ;; tell when *this* match 0 has succeeded. | |
184 | (incf offset) | |
185 | (setq re (concat "\\(" re "\\)"))) | |
186 | (setq re (syntax-propertize--shift-groups re offset)) | |
187 | (let ((code '()) | |
188 | (condition | |
189 | (cond | |
190 | ((assq 0 rule) (if (zerop offset) t | |
191 | `(match-beginning ,offset))) | |
192 | ((null (cddr rule)) | |
193 | `(match-beginning ,(+ offset (car (cadr rule))))) | |
194 | (t | |
195 | `(or ,@(mapcar | |
196 | (lambda (case) | |
197 | `(match-beginning ,(+ offset (car case)))) | |
198 | (cdr rule)))))) | |
199 | (nocode t) | |
200 | (offset offset)) | |
201 | ;; If some of the subgroup rules include Elisp code, then we | |
202 | ;; need to set the match-data so it's consistent with what the | |
203 | ;; code expects. If not, then we can simply use shifted | |
204 | ;; offset in our own code. | |
205 | (unless (zerop offset) | |
206 | (dolist (case (cdr rule)) | |
207 | (unless (stringp (cadr case)) | |
208 | (setq nocode nil))) | |
209 | (unless nocode | |
210 | (push `(let ((md (match-data 'ints))) | |
211 | ;; Keep match 0 as is, but shift everything else. | |
212 | (setcdr (cdr md) (nthcdr ,(* (1+ offset) 2) md)) | |
213 | (set-match-data md)) | |
214 | code) | |
215 | (setq offset 0))) | |
216 | ;; Now construct the code for each subgroup rules. | |
217 | (dolist (case (cdr rule)) | |
218 | (assert (null (cddr case))) | |
219 | (let* ((gn (+ offset (car case))) | |
220 | (action (nth 1 case)) | |
221 | (thiscode | |
222 | (cond | |
223 | ((stringp action) | |
224 | `((put-text-property | |
225 | (match-beginning ,gn) (match-end ,gn) | |
226 | 'syntax-table | |
227 | ',(string-to-syntax action)))) | |
228 | ((eq (car-safe action) 'ignore) | |
229 | (cdr action)) | |
230 | ((eq (car-safe action) 'prog1) | |
231 | (if (stringp (nth 1 action)) | |
232 | `((put-text-property | |
233 | (match-beginning ,gn) (match-end ,gn) | |
234 | 'syntax-table | |
235 | ',(string-to-syntax (nth 1 action))) | |
236 | ,@(nthcdr 2 action)) | |
237 | `((let ((mb (match-beginning ,gn)) | |
238 | (me (match-end ,gn)) | |
239 | (syntax ,(nth 1 action))) | |
240 | (if syntax | |
241 | (put-text-property | |
242 | mb me 'syntax-table syntax)) | |
243 | ,@(nthcdr 2 action))))) | |
244 | (t | |
245 | `((let ((mb (match-beginning ,gn)) | |
246 | (me (match-end ,gn)) | |
247 | (syntax ,action)) | |
248 | (if syntax | |
249 | (put-text-property | |
250 | mb me 'syntax-table syntax)))))))) | |
251 | ||
252 | (if (or (not (cddr rule)) (zerop gn)) | |
253 | (setq code (nconc (nreverse thiscode) code)) | |
254 | (push `(if (match-beginning ,gn) | |
255 | ;; Try and generate clean code with no | |
256 | ;; extraneous progn. | |
257 | ,(if (null (cdr thiscode)) | |
258 | (car thiscode) | |
259 | `(progn ,@thiscode))) | |
260 | code)))) | |
261 | (push (cons condition (nreverse code)) | |
262 | branches)) | |
b879a6e2 | 263 | (incf offset (regexp-opt-depth orig-re)) |
cf38dd42 SM |
264 | re)) |
265 | rules | |
266 | "\\|"))) | |
267 | `(lambda (start end) | |
268 | (goto-char start) | |
269 | (while (and (< (point) end) | |
270 | (re-search-forward ,re end t)) | |
271 | (cond ,@(nreverse branches)))))) | |
272 | ||
273 | (defun syntax-propertize-via-font-lock (keywords) | |
274 | "Propertize for syntax in START..END using font-lock syntax. | |
275 | KEYWORDS obeys the format used in `font-lock-syntactic-keywords'. | |
276 | The return value is a function suitable for `syntax-propertize-function'." | |
277 | (lexical-let ((keywords keywords)) | |
278 | (lambda (start end) | |
279 | (with-no-warnings | |
280 | (let ((font-lock-syntactic-keywords keywords)) | |
281 | (font-lock-fontify-syntactic-keywords-region start end) | |
282 | ;; In case it was eval'd/compiled. | |
283 | (setq keywords font-lock-syntactic-keywords)))))) | |
284 | ||
285 | (defun syntax-propertize (pos) | |
286 | "Ensure that syntax-table properties are set upto POS." | |
287 | (when (and syntax-propertize-function | |
288 | (< syntax-propertize--done pos)) | |
289 | ;; (message "Needs to syntax-propertize from %s to %s" | |
290 | ;; syntax-propertize--done pos) | |
291 | (set (make-local-variable 'parse-sexp-lookup-properties) t) | |
292 | (save-excursion | |
293 | (with-silent-modifications | |
294 | (let* ((start (max syntax-propertize--done (point-min))) | |
295 | (end (max pos | |
296 | (min (point-max) | |
297 | (+ start syntax-propertize-chunk-size)))) | |
298 | (funs syntax-propertize-extend-region-functions)) | |
299 | (while funs | |
300 | (let ((new (funcall (pop funs) start end))) | |
301 | (if (or (null new) | |
302 | (and (>= (car new) start) (<= (cdr new) end))) | |
303 | nil | |
304 | (setq start (car new)) | |
305 | (setq end (cdr new)) | |
306 | ;; If there's been a change, we should go through the | |
307 | ;; list again since this new position may | |
308 | ;; warrant a different answer from one of the funs we've | |
309 | ;; already seen. | |
310 | (unless (eq funs | |
311 | (cdr syntax-propertize-extend-region-functions)) | |
312 | (setq funs syntax-propertize-extend-region-functions))))) | |
313 | ;; Move the limit before calling the function, so the function | |
314 | ;; can use syntax-ppss. | |
315 | (setq syntax-propertize--done end) | |
316 | ;; (message "syntax-propertizing from %s to %s" start end) | |
317 | (remove-text-properties start end | |
318 | '(syntax-table nil syntax-multiline nil)) | |
319 | (funcall syntax-propertize-function start end)))))) | |
320 | ||
321 | ;;; Incrementally compute and memoize parser state. | |
322 | ||
88a05faf SM |
323 | (defsubst syntax-ppss-depth (ppss) |
324 | (nth 0 ppss)) | |
325 | ||
0e6c966c | 326 | (defun syntax-ppss-toplevel-pos (ppss) |
be357779 | 327 | "Get the latest syntactically outermost position found in a syntactic scan. |
9aea20c9 | 328 | PPSS is a scan state, as returned by `parse-partial-sexp' or `syntax-ppss'. |
be357779 SM |
329 | An \"outermost position\" means one that it is outside of any syntactic entity: |
330 | outside of any parentheses, comments, or strings encountered in the scan. | |
331 | If no such position is recorded in PPSS (because the end of the scan was | |
332 | itself at the outermost level), return nil." | |
6bddffd0 SM |
333 | ;; BEWARE! We rely on the undocumented 9th field. The 9th field currently |
334 | ;; contains the list of positions of the enclosing open-parens. | |
335 | ;; I.e. those positions are outside of any string/comment and the first of | |
336 | ;; those is outside of any paren (i.e. corresponds to a nil ppss). | |
337 | ;; If this list is empty but we are in a string or comment, then the 8th | |
338 | ;; field contains a similar "toplevel" position. | |
0e6c966c | 339 | (or (car (nth 9 ppss)) |
6bddffd0 | 340 | (nth 8 ppss))) |
0e6c966c | 341 | |
88a05faf SM |
342 | (defsubst syntax-ppss-context (ppss) |
343 | (cond | |
344 | ((nth 3 ppss) 'string) | |
345 | ((nth 4 ppss) 'comment) | |
346 | (t nil))) | |
347 | ||
348 | (defvar syntax-ppss-max-span 20000 | |
349 | "Threshold below which cache info is deemed unnecessary. | |
350 | We try to make sure that cache entries are at least this far apart | |
351 | from each other, to avoid keeping too much useless info.") | |
352 | ||
353 | (defvar syntax-begin-function nil | |
354 | "Function to move back outside of any comment/string/paren. | |
355 | This function should move the cursor back to some syntactically safe | |
356 | point (where the PPSS is equivalent to nil).") | |
357 | ||
358 | (defvar syntax-ppss-cache nil | |
359 | "List of (POS . PPSS) pairs, in decreasing POS order.") | |
360 | (make-variable-buffer-local 'syntax-ppss-cache) | |
361 | (defvar syntax-ppss-last nil | |
362 | "Cache of (LAST-POS . LAST-PPSS).") | |
363 | (make-variable-buffer-local 'syntax-ppss-last) | |
364 | ||
9c5b2653 SM |
365 | (defalias 'syntax-ppss-after-change-function 'syntax-ppss-flush-cache) |
366 | (defun syntax-ppss-flush-cache (beg &rest ignored) | |
367 | "Flush the cache of `syntax-ppss' starting at position BEG." | |
cf38dd42 SM |
368 | ;; Set syntax-propertize to refontify anything past beg. |
369 | (setq syntax-propertize--done (min beg syntax-propertize--done)) | |
88a05faf SM |
370 | ;; Flush invalid cache entries. |
371 | (while (and syntax-ppss-cache (> (caar syntax-ppss-cache) beg)) | |
372 | (setq syntax-ppss-cache (cdr syntax-ppss-cache))) | |
373 | ;; Throw away `last' value if made invalid. | |
374 | (when (< beg (or (car syntax-ppss-last) 0)) | |
889c5dad SM |
375 | ;; If syntax-begin-function jumped to BEG, then the old state at BEG can |
376 | ;; depend on the text after BEG (which is presumably changed). So if | |
377 | ;; BEG=(car (nth 10 syntax-ppss-last)) don't reuse that data because the | |
378 | ;; assumed nil state at BEG may not be valid any more. | |
6bddffd0 | 379 | (if (<= beg (or (syntax-ppss-toplevel-pos (cdr syntax-ppss-last)) |
8debde6e | 380 | (nth 3 syntax-ppss-last) |
889c5dad | 381 | 0)) |
88a05faf SM |
382 | (setq syntax-ppss-last nil) |
383 | (setcar syntax-ppss-last nil))) | |
384 | ;; Unregister if there's no cache left. Sadly this doesn't work | |
ad8a840d | 385 | ;; because `before-change-functions' is temporarily bound to nil here. |
88a05faf | 386 | ;; (unless syntax-ppss-cache |
ad8a840d | 387 | ;; (remove-hook 'before-change-functions 'syntax-ppss-flush-cache t)) |
88a05faf SM |
388 | ) |
389 | ||
390 | (defvar syntax-ppss-stats | |
391 | [(0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (1 . 2500.0)]) | |
392 | (defun syntax-ppss-stats () | |
e8ac59b8 SM |
393 | (mapcar (lambda (x) |
394 | (condition-case nil | |
395 | (cons (car x) (truncate (/ (cdr x) (car x)))) | |
396 | (error nil))) | |
88a05faf SM |
397 | syntax-ppss-stats)) |
398 | ||
399 | (defun syntax-ppss (&optional pos) | |
b55426e9 | 400 | "Parse-Partial-Sexp State at POS, defaulting to point. |
88a05faf SM |
401 | The returned value is the same as `parse-partial-sexp' except that |
402 | the 2nd and 6th values of the returned state cannot be relied upon. | |
88a05faf SM |
403 | Point is at POS when this function returns." |
404 | ;; Default values. | |
405 | (unless pos (setq pos (point))) | |
cf38dd42 | 406 | (syntax-propertize pos) |
a1506d29 | 407 | ;; |
88a05faf SM |
408 | (let ((old-ppss (cdr syntax-ppss-last)) |
409 | (old-pos (car syntax-ppss-last)) | |
410 | (ppss nil) | |
411 | (pt-min (point-min))) | |
412 | (if (and old-pos (> old-pos pos)) (setq old-pos nil)) | |
413 | ;; Use the OLD-POS if usable and close. Don't update the `last' cache. | |
db14504a SM |
414 | (condition-case nil |
415 | (if (and old-pos (< (- pos old-pos) | |
416 | ;; The time to use syntax-begin-function and | |
417 | ;; find PPSS is assumed to be about 2 * distance. | |
418 | (* 2 (/ (cdr (aref syntax-ppss-stats 5)) | |
419 | (1+ (car (aref syntax-ppss-stats 5))))))) | |
420 | (progn | |
421 | (incf (car (aref syntax-ppss-stats 0))) | |
422 | (incf (cdr (aref syntax-ppss-stats 0)) (- pos old-pos)) | |
423 | (parse-partial-sexp old-pos pos nil nil old-ppss)) | |
88a05faf SM |
424 | |
425 | (cond | |
db14504a SM |
426 | ;; Use OLD-PPSS if possible and close enough. |
427 | ((and (not old-pos) old-ppss | |
6bddffd0 SM |
428 | ;; If `pt-min' is too far from `pos', we could try to use |
429 | ;; other positions in (nth 9 old-ppss), but that doesn't | |
430 | ;; seem to happen in practice and it would complicate this | |
431 | ;; code (and the before-change-function code even more). | |
432 | ;; But maybe it would be useful in "degenerate" cases such | |
433 | ;; as when the whole file is wrapped in a set | |
434 | ;; of parentheses. | |
435 | (setq pt-min (or (syntax-ppss-toplevel-pos old-ppss) | |
db14504a SM |
436 | (nth 2 old-ppss))) |
437 | (<= pt-min pos) (< (- pos pt-min) syntax-ppss-max-span)) | |
438 | (incf (car (aref syntax-ppss-stats 1))) | |
439 | (incf (cdr (aref syntax-ppss-stats 1)) (- pos pt-min)) | |
440 | (setq ppss (parse-partial-sexp pt-min pos))) | |
441 | ;; The OLD-* data can't be used. Consult the cache. | |
88a05faf | 442 | (t |
db14504a SM |
443 | (let ((cache-pred nil) |
444 | (cache syntax-ppss-cache) | |
445 | (pt-min (point-min)) | |
446 | ;; I differentiate between PT-MIN and PT-BEST because | |
447 | ;; I feel like it might be important to ensure that the | |
448 | ;; cache is only filled with 100% sure data (whereas | |
449 | ;; syntax-begin-function might return incorrect data). | |
450 | ;; Maybe that's just stupid. | |
451 | (pt-best (point-min)) | |
452 | (ppss-best nil)) | |
453 | ;; look for a usable cache entry. | |
454 | (while (and cache (< pos (caar cache))) | |
455 | (setq cache-pred cache) | |
456 | (setq cache (cdr cache))) | |
457 | (if cache (setq pt-min (caar cache) ppss (cdar cache))) | |
458 | ||
ad8a840d | 459 | ;; Setup the before-change function if necessary. |
db14504a | 460 | (unless (or syntax-ppss-cache syntax-ppss-last) |
ad8a840d SM |
461 | (add-hook 'before-change-functions |
462 | 'syntax-ppss-flush-cache t t)) | |
db14504a SM |
463 | |
464 | ;; Use the best of OLD-POS and CACHE. | |
465 | (if (or (not old-pos) (< old-pos pt-min)) | |
466 | (setq pt-best pt-min ppss-best ppss) | |
467 | (incf (car (aref syntax-ppss-stats 4))) | |
468 | (incf (cdr (aref syntax-ppss-stats 4)) (- pos old-pos)) | |
469 | (setq pt-best old-pos ppss-best old-ppss)) | |
470 | ||
471 | ;; Use the `syntax-begin-function' if available. | |
472 | ;; We could try using that function earlier, but: | |
473 | ;; - The result might not be 100% reliable, so it's better to use | |
474 | ;; the cache if available. | |
475 | ;; - The function might be slow. | |
476 | ;; - If this function almost always finds a safe nearby spot, | |
477 | ;; the cache won't be populated, so consulting it is cheap. | |
478 | (when (and (not syntax-begin-function) | |
479 | (boundp 'font-lock-beginning-of-syntax-function) | |
480 | font-lock-beginning-of-syntax-function) | |
481 | (set (make-local-variable 'syntax-begin-function) | |
482 | font-lock-beginning-of-syntax-function)) | |
483 | (when (and syntax-begin-function | |
484 | (progn (goto-char pos) | |
485 | (funcall syntax-begin-function) | |
486 | ;; Make sure it's better. | |
487 | (> (point) pt-best)) | |
2e664aab SM |
488 | ;; Simple sanity checks. |
489 | (< (point) pos) ; backward-paragraph can fail here. | |
db14504a SM |
490 | (not (memq (get-text-property (point) 'face) |
491 | '(font-lock-string-face font-lock-doc-face | |
492 | font-lock-comment-face)))) | |
493 | (incf (car (aref syntax-ppss-stats 5))) | |
494 | (incf (cdr (aref syntax-ppss-stats 5)) (- pos (point))) | |
495 | (setq pt-best (point) ppss-best nil)) | |
496 | ||
497 | (cond | |
498 | ;; Quick case when we found a nearby pos. | |
499 | ((< (- pos pt-best) syntax-ppss-max-span) | |
500 | (incf (car (aref syntax-ppss-stats 2))) | |
501 | (incf (cdr (aref syntax-ppss-stats 2)) (- pos pt-best)) | |
502 | (setq ppss (parse-partial-sexp pt-best pos nil nil ppss-best))) | |
503 | ;; Slow case: compute the state from some known position and | |
504 | ;; populate the cache so we won't need to do it again soon. | |
505 | (t | |
506 | (incf (car (aref syntax-ppss-stats 3))) | |
507 | (incf (cdr (aref syntax-ppss-stats 3)) (- pos pt-min)) | |
508 | ||
509 | ;; If `pt-min' is too far, add a few intermediate entries. | |
510 | (while (> (- pos pt-min) (* 2 syntax-ppss-max-span)) | |
511 | (setq ppss (parse-partial-sexp | |
512 | pt-min (setq pt-min (/ (+ pt-min pos) 2)) | |
513 | nil nil ppss)) | |
514 | (let ((pair (cons pt-min ppss))) | |
515 | (if cache-pred | |
516 | (push pair (cdr cache-pred)) | |
517 | (push pair syntax-ppss-cache)))) | |
518 | ||
519 | ;; Compute the actual return value. | |
520 | (setq ppss (parse-partial-sexp pt-min pos nil nil ppss)) | |
521 | ||
522 | ;; Debugging check. | |
523 | ;; (let ((real-ppss (parse-partial-sexp (point-min) pos))) | |
524 | ;; (setcar (last ppss 4) 0) | |
525 | ;; (setcar (last real-ppss 4) 0) | |
526 | ;; (setcar (last ppss 8) nil) | |
527 | ;; (setcar (last real-ppss 8) nil) | |
528 | ;; (unless (equal ppss real-ppss) | |
529 | ;; (message "!!Syntax: %s != %s" ppss real-ppss) | |
530 | ;; (setq ppss real-ppss))) | |
531 | ||
532 | ;; Store it in the cache. | |
533 | (let ((pair (cons pos ppss))) | |
534 | (if cache-pred | |
535 | (if (> (- (caar cache-pred) pos) syntax-ppss-max-span) | |
536 | (push pair (cdr cache-pred)) | |
537 | (setcar cache-pred pair)) | |
538 | (if (or (null syntax-ppss-cache) | |
539 | (> (- (caar syntax-ppss-cache) pos) | |
540 | syntax-ppss-max-span)) | |
541 | (push pair syntax-ppss-cache) | |
542 | (setcar syntax-ppss-cache pair))))))))) | |
543 | ||
544 | (setq syntax-ppss-last (cons pos ppss)) | |
545 | ppss) | |
546 | (args-out-of-range | |
547 | ;; If the buffer is more narrowed than when we built the cache, | |
548 | ;; we may end up calling parse-partial-sexp with a position before | |
549 | ;; point-min. In that case, just parse from point-min assuming | |
550 | ;; a nil state. | |
551 | (parse-partial-sexp (point-min) pos))))) | |
88a05faf SM |
552 | |
553 | ;; Debugging functions | |
554 | ||
555 | (defun syntax-ppss-debug () | |
556 | (let ((pt nil) | |
557 | (min-diffs nil)) | |
558 | (dolist (x (append syntax-ppss-cache (list (cons (point-min) nil)))) | |
559 | (when pt (push (- pt (car x)) min-diffs)) | |
560 | (setq pt (car x))) | |
561 | min-diffs)) | |
562 | ||
563 | ;; XEmacs compatibility functions | |
564 | ||
565 | ;; (defun buffer-syntactic-context (&optional buffer) | |
566 | ;; "Syntactic context at point in BUFFER. | |
567 | ;; Either of `string', `comment' or `nil'. | |
568 | ;; This is an XEmacs compatibility function." | |
569 | ;; (with-current-buffer (or buffer (current-buffer)) | |
570 | ;; (syntax-ppss-context (syntax-ppss)))) | |
571 | ||
572 | ;; (defun buffer-syntactic-context-depth (&optional buffer) | |
573 | ;; "Syntactic parenthesis depth at point in BUFFER. | |
574 | ;; This is an XEmacs compatibility function." | |
575 | ;; (with-current-buffer (or buffer (current-buffer)) | |
576 | ;; (syntax-ppss-depth (syntax-ppss)))) | |
577 | ||
88a05faf | 578 | (provide 'syntax) |
ab5796a9 | 579 | |
88a05faf | 580 | ;;; syntax.el ends here |