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f62be99b CW |
1 | ;;; font-core.el --- Core interface to font-lock |
2 | ||
3 | ;; Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 1999, 2000, 2001, 2002 | |
4 | ;; Free Software Foundation, Inc. | |
5 | ||
6 | ;; Maintainer: FSF | |
7 | ;; Keywords: languages, faces | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
14 | ;; any later version. | |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
25 | ||
26 | ;;; Code: | |
27 | ||
2dc20ca8 RS |
28 | (defvar font-lock-maximum-size) |
29 | (defvar font-lock-verbose) | |
30 | ||
f62be99b CW |
31 | ;; This variable is used by mode packages that support Font Lock mode by |
32 | ;; defining their own keywords to use for `font-lock-keywords'. (The mode | |
33 | ;; command should make it buffer-local and set it to provide the set up.) | |
34 | (defvar font-lock-defaults nil | |
35 | "Defaults for Font Lock mode specified by the major mode. | |
36 | Defaults should be of the form: | |
37 | ||
38 | (KEYWORDS KEYWORDS-ONLY CASE-FOLD SYNTAX-ALIST SYNTAX-BEGIN ...) | |
39 | ||
40 | KEYWORDS may be a symbol (a variable or function whose value is the keywords to | |
41 | use for fontification) or a list of symbols. If KEYWORDS-ONLY is non-nil, | |
42 | syntactic fontification (strings and comments) is not performed. | |
43 | If CASE-FOLD is non-nil, the case of the keywords is ignored when fontifying. | |
44 | If SYNTAX-ALIST is non-nil, it should be a list of cons pairs of the form | |
45 | \(CHAR-OR-STRING . STRING) used to set the local Font Lock syntax table, for | |
46 | keyword and syntactic fontification (see `modify-syntax-entry'). | |
47 | ||
48 | If SYNTAX-BEGIN is non-nil, it should be a function with no args used to move | |
49 | backwards outside any enclosing syntactic block, for syntactic fontification. | |
50 | Typical values are `beginning-of-line' (i.e., the start of the line is known to | |
51 | be outside a syntactic block), or `beginning-of-defun' for programming modes or | |
52 | `backward-paragraph' for textual modes (i.e., the mode-dependent function is | |
53 | known to move outside a syntactic block). If nil, the beginning of the buffer | |
54 | is used as a position outside of a syntactic block, in the worst case. | |
55 | ||
56 | These item elements are used by Font Lock mode to set the variables | |
57 | `font-lock-keywords', `font-lock-keywords-only', | |
58 | `font-lock-keywords-case-fold-search', `font-lock-syntax-table' and | |
59 | `font-lock-beginning-of-syntax-function', respectively. | |
60 | ||
61 | Further item elements are alists of the form (VARIABLE . VALUE) and are in no | |
62 | particular order. Each VARIABLE is made buffer-local before set to VALUE. | |
63 | ||
64 | Currently, appropriate variables include `font-lock-mark-block-function'. | |
65 | If this is non-nil, it should be a function with no args used to mark any | |
66 | enclosing block of text, for fontification via \\[font-lock-fontify-block]. | |
67 | Typical values are `mark-defun' for programming modes or `mark-paragraph' for | |
68 | textual modes (i.e., the mode-dependent function is known to put point and mark | |
69 | around a text block relevant to that mode). | |
70 | ||
71 | Other variables include that for syntactic keyword fontification, | |
72 | `font-lock-syntactic-keywords' | |
f7abda1e | 73 | and those for buffer-specialized fontification functions, |
f62be99b CW |
74 | `font-lock-fontify-buffer-function', `font-lock-unfontify-buffer-function', |
75 | `font-lock-fontify-region-function', `font-lock-unfontify-region-function', | |
76 | `font-lock-inhibit-thing-lock' and `font-lock-maximum-size'.") | |
77 | (make-variable-buffer-local 'font-lock-defaults) | |
78 | ||
79 | ;; This variable is used where font-lock.el itself supplies the | |
80 | ;; keywords. Really, this shouldn't need to be in font-core.el, but | |
81 | ;; we can't avoid it. In the future, this stuff will hopefully be | |
82 | ;; moved to cc-mode itself. | |
83 | (defvar font-lock-defaults-alist | |
84 | (let (;; We use `beginning-of-defun', rather than nil, for SYNTAX-BEGIN. | |
85 | ;; Thus the calculation of the cache is usually faster but not | |
86 | ;; infallible, so we risk mis-fontification. sm. | |
87 | (c-mode-defaults | |
88 | '((c-font-lock-keywords c-font-lock-keywords-1 | |
89 | c-font-lock-keywords-2 c-font-lock-keywords-3) | |
90 | nil nil ((?_ . "w")) beginning-of-defun | |
91 | (font-lock-syntactic-face-function | |
92 | . c-font-lock-syntactic-face-function) | |
93 | (font-lock-mark-block-function . mark-defun))) | |
94 | (c++-mode-defaults | |
95 | '((c++-font-lock-keywords c++-font-lock-keywords-1 | |
96 | c++-font-lock-keywords-2 c++-font-lock-keywords-3) | |
97 | nil nil ((?_ . "w")) beginning-of-defun | |
98 | (font-lock-syntactic-face-function | |
99 | . c-font-lock-syntactic-face-function) | |
100 | (font-lock-mark-block-function . mark-defun))) | |
101 | (objc-mode-defaults | |
102 | '((objc-font-lock-keywords objc-font-lock-keywords-1 | |
103 | objc-font-lock-keywords-2 objc-font-lock-keywords-3) | |
104 | nil nil ((?_ . "w") (?$ . "w")) nil | |
105 | (font-lock-syntactic-face-function | |
106 | . c-font-lock-syntactic-face-function) | |
107 | (font-lock-mark-block-function . mark-defun))) | |
108 | (java-mode-defaults | |
109 | '((java-font-lock-keywords java-font-lock-keywords-1 | |
110 | java-font-lock-keywords-2 java-font-lock-keywords-3) | |
111 | nil nil ((?_ . "w") (?$ . "w")) nil | |
112 | (font-lock-syntactic-face-function | |
113 | . java-font-lock-syntactic-face-function) | |
114 | (font-lock-mark-block-function . mark-defun)))) | |
115 | (list | |
116 | (cons 'c-mode c-mode-defaults) | |
117 | (cons 'c++-mode c++-mode-defaults) | |
118 | (cons 'objc-mode objc-mode-defaults) | |
119 | (cons 'java-mode java-mode-defaults))) | |
120 | "Alist of fall-back Font Lock defaults for major modes. | |
121 | ||
122 | This variable should not be used any more. | |
123 | Set the buffer-local `font-lock-keywords' in the major mode instead. | |
124 | ||
125 | Each item should be a list of the form: | |
126 | ||
127 | (MAJOR-MODE . FONT-LOCK-DEFAULTS) | |
128 | ||
129 | where MAJOR-MODE is a symbol and FONT-LOCK-DEFAULTS is a list of default | |
130 | settings. See the variable `font-lock-defaults', which takes precedence.") | |
131 | (make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults) | |
132 | ||
133 | (defvar font-lock-multiline nil | |
134 | "Whether font-lock should cater to multiline keywords. | |
135 | If nil, don't try to handle multiline patterns. | |
136 | If t, always handle multiline patterns. | |
137 | If `undecided', don't try to handle multiline patterns until you see one. | |
138 | Major/minor modes can set this variable if they know which option applies.") | |
139 | ||
140 | (defvar font-lock-fontified nil) ; Whether we have fontified the buffer. | |
141 | ||
7c4ef9b3 CW |
142 | (defvar font-lock-function 'font-lock-default-function |
143 | "A function which is called when `font-lock-mode' is toggled. | |
144 | It will be passed one argument, which is the current value of | |
145 | `font-lock-mode'.") | |
3e119830 | 146 | (make-variable-buffer-local 'font-lock-function) |
7c4ef9b3 | 147 | |
f62be99b CW |
148 | (define-minor-mode font-lock-mode |
149 | "Toggle Font Lock mode. | |
150 | With arg, turn Font Lock mode off if and only if arg is a non-positive | |
151 | number; if arg is nil, toggle Font Lock mode; anything else turns Font | |
152 | Lock on. | |
153 | \(Font Lock is also known as \"syntax highlighting\".) | |
154 | ||
155 | When Font Lock mode is enabled, text is fontified as you type it: | |
156 | ||
157 | - Comments are displayed in `font-lock-comment-face'; | |
158 | - Strings are displayed in `font-lock-string-face'; | |
159 | - Certain other expressions are displayed in other faces according to the | |
160 | value of the variable `font-lock-keywords'. | |
161 | ||
162 | To customize the faces (colors, fonts, etc.) used by Font Lock for | |
163 | fontifying different parts of buffer text, use \\[customize-face]. | |
164 | ||
165 | You can enable Font Lock mode in any major mode automatically by turning on in | |
166 | the major mode's hook. For example, put in your ~/.emacs: | |
167 | ||
168 | (add-hook 'c-mode-hook 'turn-on-font-lock) | |
169 | ||
170 | Alternatively, you can use Global Font Lock mode to automagically turn on Font | |
171 | Lock mode in buffers whose major mode supports it and whose major mode is one | |
172 | of `font-lock-global-modes'. For example, put in your ~/.emacs: | |
173 | ||
174 | (global-font-lock-mode t) | |
175 | ||
176 | There are a number of support modes that may be used to speed up Font Lock mode | |
177 | in various ways, specified via the variable `font-lock-support-mode'. Where | |
178 | major modes support different levels of fontification, you can use the variable | |
179 | `font-lock-maximum-decoration' to specify which level you generally prefer. | |
180 | When you turn Font Lock mode on/off the buffer is fontified/defontified, though | |
181 | fontification occurs only if the buffer is less than `font-lock-maximum-size'. | |
182 | ||
183 | For example, to specify that Font Lock mode use use Lazy Lock mode as a support | |
184 | mode and use maximum levels of fontification, put in your ~/.emacs: | |
185 | ||
186 | (setq font-lock-support-mode 'lazy-lock-mode) | |
187 | (setq font-lock-maximum-decoration t) | |
188 | ||
189 | To add your own highlighting for some major mode, and modify the highlighting | |
190 | selected automatically via the variable `font-lock-maximum-decoration', you can | |
191 | use `font-lock-add-keywords'. | |
192 | ||
193 | To fontify a buffer, without turning on Font Lock mode and regardless of buffer | |
194 | size, you can use \\[font-lock-fontify-buffer]. | |
195 | ||
196 | To fontify a block (the function or paragraph containing point, or a number of | |
197 | lines around point), perhaps because modification on the current line caused | |
198 | syntactic change on other lines, you can use \\[font-lock-fontify-block]. | |
199 | ||
200 | See the variable `font-lock-defaults-alist' for the Font Lock mode default | |
201 | settings. You can set your own default settings for some mode, by setting a | |
7c4ef9b3 CW |
202 | buffer local value for `font-lock-defaults', via its mode hook. |
203 | ||
204 | The above is the default behavior of `font-lock-mode'; you may specify | |
205 | your own function which is called when `font-lock-mode' is toggled via | |
206 | `font-lock-function'. " | |
f62be99b CW |
207 | nil nil nil |
208 | ;; Don't turn on Font Lock mode if we don't have a display (we're running a | |
209 | ;; batch job) or if the buffer is invisible (the name starts with a space). | |
210 | (when (or noninteractive (eq (aref (buffer-name) 0) ?\ )) | |
211 | (setq font-lock-mode nil)) | |
8e97108f RS |
212 | (funcall font-lock-function font-lock-mode) |
213 | ;; Arrange to unfontify this buffer if we change major mode later. | |
214 | (if font-lock-mode | |
2dc20ca8 RS |
215 | (add-hook 'change-major-mode-hook 'font-lock-change-mode nil t) |
216 | (remove-hook 'change-major-mode-hook 'font-lock-change-mode t))) | |
217 | ||
218 | ;; Get rid of fontification for the old major mode. | |
219 | ;; We do this when changing major modes. | |
220 | (defun font-lock-change-mode () | |
40e2bbe9 SM |
221 | (font-lock-mode -1)) |
222 | ||
67c9f58d RS |
223 | (defun font-lock-defontify () |
224 | "Clear out all `font-lock-face' properties in current buffer. | |
225 | A major mode that uses `font-lock-face' properties should put | |
226 | this function onto `change-major-mode-hook'." | |
227 | (let ((modp (buffer-modified-p)) | |
228 | (inhibit-read-only t)) | |
229 | (save-restriction | |
230 | (widen) | |
231 | (remove-list-of-text-properties (point-min) (point-max) | |
232 | '(font-lock-face))) | |
233 | (set-buffer-modified-p modp))) | |
234 | ||
40e2bbe9 | 235 | (defun font-lock-default-function (mode) |
f62be99b | 236 | ;; Turn on Font Lock mode. |
40e2bbe9 | 237 | (when mode |
f62be99b | 238 | (font-lock-set-defaults) |
1b6adddb CW |
239 | (set (make-local-variable 'char-property-alias-alist) |
240 | (copy-tree char-property-alias-alist)) | |
241 | ;; Add `font-lock-face' as an alias for the `face' property. | |
242 | (let ((elt (assq 'face char-property-alias-alist))) | |
243 | (if elt | |
244 | (unless (memq 'font-lock-face (cdr elt)) | |
245 | (setcdr elt (nconc (cdr elt) (list 'font-lock-face)))) | |
246 | (push (list 'face 'font-lock-face) char-property-alias-alist))) | |
247 | ;; Only do hard work if the mode has specified stuff in | |
248 | ;; `font-lock-defaults'. | |
61fd2c68 | 249 | (when font-lock-defaults |
f62be99b CW |
250 | (add-hook 'after-change-functions 'font-lock-after-change-function t t) |
251 | (font-lock-turn-on-thing-lock) | |
252 | ;; Fontify the buffer if we have to. | |
253 | (let ((max-size (font-lock-value-in-major-mode font-lock-maximum-size))) | |
254 | (cond (font-lock-fontified | |
255 | nil) | |
256 | ((or (null max-size) (> max-size (buffer-size))) | |
257 | (font-lock-fontify-buffer)) | |
258 | (font-lock-verbose | |
259 | (message "Fontifying %s...buffer size greater than font-lock-maximum-size" | |
260 | (buffer-name))))))) | |
261 | ;; Turn off Font Lock mode. | |
40e2bbe9 | 262 | (unless mode |
1b6adddb CW |
263 | ;; Remove `font-lock-face' as an alias for the `face' property. |
264 | (set (make-local-variable 'char-property-alias-alist) | |
265 | (copy-tree char-property-alias-alist)) | |
266 | (let ((elt (assq 'face char-property-alias-alist))) | |
267 | (when elt | |
268 | (setcdr elt (remq 'font-lock-face (cdr elt))) | |
269 | (when (null (cdr elt)) | |
270 | (setq char-property-alias-alist (delq elt char-property-alias-alist))))) | |
61fd2c68 | 271 | (when font-lock-defaults |
f62be99b CW |
272 | (remove-hook 'after-change-functions 'font-lock-after-change-function t) |
273 | (font-lock-unfontify-buffer) | |
274 | (font-lock-turn-off-thing-lock)))) | |
71296446 | 275 | |
f62be99b CW |
276 | (defun turn-on-font-lock () |
277 | "Turn on Font Lock mode (only if the terminal can display it)." | |
278 | (unless font-lock-mode | |
279 | (font-lock-mode))) | |
280 | ||
281 | (defvar font-lock-set-defaults nil) ; Whether we have set up defaults. | |
282 | ||
283 | (defun font-lock-set-defaults () | |
284 | "Set fontification defaults appropriately for this mode. | |
285 | Sets various variables using `font-lock-defaults' (or, if nil, using | |
286 | `font-lock-defaults-alist') and `font-lock-maximum-decoration'." | |
287 | (unless font-lock-set-defaults | |
288 | (set (make-local-variable 'font-lock-set-defaults) t) | |
289 | (make-local-variable 'font-lock-fontified) | |
290 | (make-local-variable 'font-lock-multiline) | |
660acebe | 291 | (let ((defaults (or font-lock-defaults |
33260712 | 292 | (cdr (assq major-mode font-lock-defaults-alist))))) |
61fd2c68 | 293 | (when defaults |
660acebe CW |
294 | (require 'font-lock) |
295 | (font-lock-set-defaults-1))))) | |
f62be99b CW |
296 | |
297 | ;;; Global Font Lock mode. | |
298 | ||
299 | ;; A few people have hassled in the past for a way to make it easier to turn on | |
300 | ;; Font Lock mode, without the user needing to know for which modes s/he has to | |
301 | ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always | |
302 | ;; balked at that way, as I see it as just re-moulding the same problem in | |
303 | ;; another form. That is; some person would still have to keep track of which | |
304 | ;; modes (which may not even be distributed with Emacs) support Font Lock mode. | |
305 | ;; The list would always be out of date. And that person might have to be me. | |
306 | ||
307 | ;; Implementation. | |
308 | ;; | |
309 | ;; In a previous discussion the following hack came to mind. It is a gross | |
310 | ;; hack, but it generally works. We use the convention that major modes start | |
311 | ;; by calling the function `kill-all-local-variables', which in turn runs | |
312 | ;; functions on the hook variable `change-major-mode-hook'. We attach our | |
313 | ;; function `font-lock-change-major-mode' to that hook. Of course, when this | |
314 | ;; hook is run, the major mode is in the process of being changed and we do not | |
315 | ;; know what the final major mode will be. So, `font-lock-change-major-mode' | |
316 | ;; only (a) notes the name of the current buffer, and (b) adds our function | |
1a4914f3 | 317 | ;; `turn-on-font-lock-if-enabled' to the hook variables `find-file-hook' and |
f62be99b CW |
318 | ;; `post-command-hook' (for buffers that are not visiting files). By the time |
319 | ;; the functions on the first of these hooks to be run are run, the new major | |
320 | ;; mode is assumed to be in place. This way we get a Font Lock function run | |
321 | ;; when a major mode is turned on, without knowing major modes or their hooks. | |
322 | ;; | |
323 | ;; Naturally this requires that (a) major modes run `kill-all-local-variables', | |
324 | ;; as they are supposed to do, and (b) the major mode is in place after the | |
325 | ;; file is visited or the command that ran `kill-all-local-variables' has | |
326 | ;; finished, whichever the sooner. Arguably, any major mode that does not | |
327 | ;; follow the convension (a) is broken, and I can't think of any reason why (b) | |
328 | ;; would not be met (except `gnudoit' on non-files). However, it is not clean. | |
329 | ;; | |
330 | ;; Probably the cleanest solution is to have each major mode function run some | |
331 | ;; hook, e.g., `major-mode-hook', but maybe implementing that change is | |
332 | ;; impractical. I am personally against making `setq' a macro or be advised, | |
333 | ;; or have a special function such as `set-major-mode', but maybe someone can | |
334 | ;; come up with another solution? | |
335 | ||
336 | ;; User interface. | |
337 | ;; | |
338 | ;; Although Global Font Lock mode is a pseudo-mode, I think that the user | |
339 | ;; interface should conform to the usual Emacs convention for modes, i.e., a | |
340 | ;; command to toggle the feature (`global-font-lock-mode') with a variable for | |
341 | ;; finer control of the mode's behaviour (`font-lock-global-modes'). | |
342 | ;; | |
343 | ;; The feature should not be enabled by loading font-lock.el, since other | |
344 | ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or | |
345 | ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be | |
346 | ;; turned on everywhere. That would not be intuitive or informative because | |
347 | ;; loading a file tells you nothing about the feature or how to control it. It | |
348 | ;; would also be contrary to the Principle of Least Surprise. sm. | |
349 | ||
350 | (defcustom font-lock-global-modes t | |
351 | "*Modes for which Font Lock mode is automagically turned on. | |
352 | Global Font Lock mode is controlled by the command `global-font-lock-mode'. | |
353 | If nil, means no modes have Font Lock mode automatically turned on. | |
354 | If t, all modes that support Font Lock mode have it automatically turned on. | |
355 | If a list, it should be a list of `major-mode' symbol names for which Font Lock | |
356 | mode should be automatically turned on. The sense of the list is negated if it | |
357 | begins with `not'. For example: | |
358 | (c-mode c++-mode) | |
359 | means that Font Lock mode is turned on for buffers in C and C++ modes only." | |
360 | :type '(choice (const :tag "none" nil) | |
361 | (const :tag "all" t) | |
362 | (set :menu-tag "mode specific" :tag "modes" | |
363 | :value (not) | |
364 | (const :tag "Except" not) | |
365 | (repeat :inline t (symbol :tag "mode")))) | |
366 | :group 'font-lock) | |
367 | ||
368 | (defun turn-on-font-lock-if-enabled () | |
61fd2c68 CW |
369 | (unless (and (eq (car-safe font-lock-global-modes) 'not) |
370 | (memq major-mode (cdr font-lock-global-modes))) | |
f62be99b CW |
371 | (let (inhibit-quit) |
372 | (turn-on-font-lock)))) | |
373 | ||
374 | (easy-mmode-define-global-mode | |
375 | global-font-lock-mode font-lock-mode turn-on-font-lock-if-enabled | |
376 | :extra-args (dummy)) | |
377 | ||
378 | ;;; End of Global Font Lock mode. | |
379 | ||
380 | (provide 'font-core) | |
381 | ||
382 | ;;; font-core.el ends here | |
383 |