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f62be99b CW |
1 | ;;; font-core.el --- Core interface to font-lock |
2 | ||
30b940a7 | 3 | ;; Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, |
ae940284 | 4 | ;; 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
f62be99b CW |
5 | |
6 | ;; Maintainer: FSF | |
7 | ;; Keywords: languages, faces | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
eb3fa2cf | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
f62be99b | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
f62be99b CW |
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 | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
f62be99b CW |
23 | |
24 | ;;; Code: | |
25 | ||
26 | ;; This variable is used by mode packages that support Font Lock mode by | |
27 | ;; defining their own keywords to use for `font-lock-keywords'. (The mode | |
28 | ;; command should make it buffer-local and set it to provide the set up.) | |
29 | (defvar font-lock-defaults nil | |
30 | "Defaults for Font Lock mode specified by the major mode. | |
31 | Defaults should be of the form: | |
32 | ||
77f5a70d | 33 | (KEYWORDS [KEYWORDS-ONLY [CASE-FOLD [SYNTAX-ALIST [SYNTAX-BEGIN ...]]]]) |
f62be99b | 34 | |
5ff602de GM |
35 | KEYWORDS may be a symbol (a variable or function whose value is the keywords |
36 | to use for fontification) or a list of symbols (specifying different levels | |
37 | of fontification). | |
38 | ||
39 | If KEYWORDS-ONLY is non-nil, syntactic fontification (strings and | |
40 | comments) is not performed. | |
41 | ||
f62be99b | 42 | If CASE-FOLD is non-nil, the case of the keywords is ignored when fontifying. |
5ff602de | 43 | |
f62be99b CW |
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 | ||
5ff602de GM |
56 | \(See also Info node `(elisp)Font Lock Basics'.) |
57 | ||
f62be99b CW |
58 | These item elements are used by Font Lock mode to set the variables |
59 | `font-lock-keywords', `font-lock-keywords-only', | |
60 | `font-lock-keywords-case-fold-search', `font-lock-syntax-table' and | |
61 | `font-lock-beginning-of-syntax-function', respectively. | |
62 | ||
63 | Further item elements are alists of the form (VARIABLE . VALUE) and are in no | |
64 | particular order. Each VARIABLE is made buffer-local before set to VALUE. | |
65 | ||
66 | Currently, appropriate variables include `font-lock-mark-block-function'. | |
67 | If this is non-nil, it should be a function with no args used to mark any | |
68 | enclosing block of text, for fontification via \\[font-lock-fontify-block]. | |
69 | Typical values are `mark-defun' for programming modes or `mark-paragraph' for | |
70 | textual modes (i.e., the mode-dependent function is known to put point and mark | |
71 | around a text block relevant to that mode). | |
72 | ||
73 | Other variables include that for syntactic keyword fontification, | |
77f5a70d LK |
74 | `font-lock-syntactic-keywords' and those for buffer-specialized fontification |
75 | functions, `font-lock-fontify-buffer-function', | |
76 | `font-lock-unfontify-buffer-function', `font-lock-fontify-region-function', | |
77 | `font-lock-unfontify-region-function', and `font-lock-inhibit-thing-lock'.") | |
6dc3311d GM |
78 | ;; Autoload if this file no longer dumped. |
79 | (put 'font-lock-defaults 'risky-local-variable t) | |
f62be99b CW |
80 | (make-variable-buffer-local 'font-lock-defaults) |
81 | ||
ebd872c8 | 82 | (defvar font-lock-defaults-alist nil |
f62be99b CW |
83 | "Alist of fall-back Font Lock defaults for major modes. |
84 | ||
f62be99b CW |
85 | Each item should be a list of the form: |
86 | ||
87 | (MAJOR-MODE . FONT-LOCK-DEFAULTS) | |
88 | ||
89 | where MAJOR-MODE is a symbol and FONT-LOCK-DEFAULTS is a list of default | |
90 | settings. See the variable `font-lock-defaults', which takes precedence.") | |
7df7eb04 | 91 | (make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults "21.1") |
f62be99b | 92 | |
7c4ef9b3 CW |
93 | (defvar font-lock-function 'font-lock-default-function |
94 | "A function which is called when `font-lock-mode' is toggled. | |
95 | It will be passed one argument, which is the current value of | |
96 | `font-lock-mode'.") | |
7c4ef9b3 | 97 | |
642b63e8 LT |
98 | ;; The mode for which font-lock was initialized, or nil if none. |
99 | (defvar font-lock-mode-major-mode) | |
f62be99b CW |
100 | (define-minor-mode font-lock-mode |
101 | "Toggle Font Lock mode. | |
102 | With arg, turn Font Lock mode off if and only if arg is a non-positive | |
103 | number; if arg is nil, toggle Font Lock mode; anything else turns Font | |
104 | Lock on. | |
105 | \(Font Lock is also known as \"syntax highlighting\".) | |
106 | ||
107 | When Font Lock mode is enabled, text is fontified as you type it: | |
108 | ||
109 | - Comments are displayed in `font-lock-comment-face'; | |
110 | - Strings are displayed in `font-lock-string-face'; | |
111 | - Certain other expressions are displayed in other faces according to the | |
112 | value of the variable `font-lock-keywords'. | |
113 | ||
114 | To customize the faces (colors, fonts, etc.) used by Font Lock for | |
115 | fontifying different parts of buffer text, use \\[customize-face]. | |
116 | ||
117 | You can enable Font Lock mode in any major mode automatically by turning on in | |
118 | the major mode's hook. For example, put in your ~/.emacs: | |
119 | ||
120 | (add-hook 'c-mode-hook 'turn-on-font-lock) | |
121 | ||
122 | Alternatively, you can use Global Font Lock mode to automagically turn on Font | |
123 | Lock mode in buffers whose major mode supports it and whose major mode is one | |
124 | of `font-lock-global-modes'. For example, put in your ~/.emacs: | |
125 | ||
126 | (global-font-lock-mode t) | |
127 | ||
ea5b829c RF |
128 | Where major modes support different levels of fontification, you can use |
129 | the variable `font-lock-maximum-decoration' to specify which level you | |
130 | generally prefer. When you turn Font Lock mode on/off the buffer is | |
131 | fontified/defontified, though fontification occurs only if the buffer is | |
132 | less than `font-lock-maximum-size'. | |
f62be99b | 133 | |
f62be99b CW |
134 | To add your own highlighting for some major mode, and modify the highlighting |
135 | selected automatically via the variable `font-lock-maximum-decoration', you can | |
136 | use `font-lock-add-keywords'. | |
137 | ||
138 | To fontify a buffer, without turning on Font Lock mode and regardless of buffer | |
139 | size, you can use \\[font-lock-fontify-buffer]. | |
140 | ||
141 | To fontify a block (the function or paragraph containing point, or a number of | |
142 | lines around point), perhaps because modification on the current line caused | |
143 | syntactic change on other lines, you can use \\[font-lock-fontify-block]. | |
144 | ||
145 | See the variable `font-lock-defaults-alist' for the Font Lock mode default | |
146 | settings. You can set your own default settings for some mode, by setting a | |
7c4ef9b3 CW |
147 | buffer local value for `font-lock-defaults', via its mode hook. |
148 | ||
149 | The above is the default behavior of `font-lock-mode'; you may specify | |
150 | your own function which is called when `font-lock-mode' is toggled via | |
151 | `font-lock-function'. " | |
9324f671 | 152 | nil nil nil |
f62be99b CW |
153 | ;; Don't turn on Font Lock mode if we don't have a display (we're running a |
154 | ;; batch job) or if the buffer is invisible (the name starts with a space). | |
5a4689d9 | 155 | (when (or noninteractive (eq (aref (buffer-name) 0) ?\s)) |
f62be99b | 156 | (setq font-lock-mode nil)) |
8e97108f RS |
157 | (funcall font-lock-function font-lock-mode) |
158 | ;; Arrange to unfontify this buffer if we change major mode later. | |
159 | (if font-lock-mode | |
2dc20ca8 | 160 | (add-hook 'change-major-mode-hook 'font-lock-change-mode nil t) |
642b63e8 LT |
161 | (remove-hook 'change-major-mode-hook 'font-lock-change-mode t)) |
162 | (when font-lock-mode | |
163 | (setq font-lock-mode-major-mode major-mode))) | |
2dc20ca8 RS |
164 | |
165 | ;; Get rid of fontification for the old major mode. | |
166 | ;; We do this when changing major modes. | |
167 | (defun font-lock-change-mode () | |
40e2bbe9 SM |
168 | (font-lock-mode -1)) |
169 | ||
67c9f58d RS |
170 | (defun font-lock-defontify () |
171 | "Clear out all `font-lock-face' properties in current buffer. | |
e350babd | 172 | A major mode that uses `font-lock-face' properties might want to put |
67c9f58d RS |
173 | this function onto `change-major-mode-hook'." |
174 | (let ((modp (buffer-modified-p)) | |
175 | (inhibit-read-only t)) | |
176 | (save-restriction | |
177 | (widen) | |
178 | (remove-list-of-text-properties (point-min) (point-max) | |
179 | '(font-lock-face))) | |
bb125ff0 | 180 | (restore-buffer-modified-p modp))) |
67c9f58d | 181 | |
642b63e8 | 182 | (defvar font-lock-set-defaults) |
40e2bbe9 | 183 | (defun font-lock-default-function (mode) |
f62be99b | 184 | ;; Turn on Font Lock mode. |
40e2bbe9 | 185 | (when mode |
1b6adddb CW |
186 | (set (make-local-variable 'char-property-alias-alist) |
187 | (copy-tree char-property-alias-alist)) | |
188 | ;; Add `font-lock-face' as an alias for the `face' property. | |
189 | (let ((elt (assq 'face char-property-alias-alist))) | |
190 | (if elt | |
191 | (unless (memq 'font-lock-face (cdr elt)) | |
192 | (setcdr elt (nconc (cdr elt) (list 'font-lock-face)))) | |
e350babd | 193 | (push (list 'face 'font-lock-face) char-property-alias-alist)))) |
f62be99b | 194 | ;; Turn off Font Lock mode. |
40e2bbe9 | 195 | (unless mode |
1b6adddb CW |
196 | ;; Remove `font-lock-face' as an alias for the `face' property. |
197 | (set (make-local-variable 'char-property-alias-alist) | |
198 | (copy-tree char-property-alias-alist)) | |
199 | (let ((elt (assq 'face char-property-alias-alist))) | |
200 | (when elt | |
201 | (setcdr elt (remq 'font-lock-face (cdr elt))) | |
202 | (when (null (cdr elt)) | |
e350babd SM |
203 | (setq char-property-alias-alist |
204 | (delq elt char-property-alias-alist)))))) | |
205 | ||
206 | ;; Only do hard work if the mode has specified stuff in | |
207 | ;; `font-lock-defaults'. | |
208 | (when (or font-lock-defaults | |
642b63e8 | 209 | (if (boundp 'font-lock-keywords) font-lock-keywords) |
723c911c | 210 | (with-no-warnings |
642b63e8 LT |
211 | (cdr (assq major-mode font-lock-defaults-alist))) |
212 | (and mode | |
213 | (boundp 'font-lock-set-defaults) | |
214 | font-lock-set-defaults | |
215 | font-lock-mode-major-mode | |
216 | (not (eq font-lock-mode-major-mode major-mode)))) | |
e350babd | 217 | (font-lock-mode-internal mode))) |
71296446 | 218 | |
f62be99b CW |
219 | (defun turn-on-font-lock () |
220 | "Turn on Font Lock mode (only if the terminal can display it)." | |
221 | (unless font-lock-mode | |
222 | (font-lock-mode))) | |
223 | ||
f62be99b CW |
224 | ;;; Global Font Lock mode. |
225 | ||
226 | ;; A few people have hassled in the past for a way to make it easier to turn on | |
227 | ;; Font Lock mode, without the user needing to know for which modes s/he has to | |
228 | ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always | |
229 | ;; balked at that way, as I see it as just re-moulding the same problem in | |
230 | ;; another form. That is; some person would still have to keep track of which | |
231 | ;; modes (which may not even be distributed with Emacs) support Font Lock mode. | |
232 | ;; The list would always be out of date. And that person might have to be me. | |
233 | ||
234 | ;; Implementation. | |
235 | ;; | |
236 | ;; In a previous discussion the following hack came to mind. It is a gross | |
237 | ;; hack, but it generally works. We use the convention that major modes start | |
238 | ;; by calling the function `kill-all-local-variables', which in turn runs | |
239 | ;; functions on the hook variable `change-major-mode-hook'. We attach our | |
240 | ;; function `font-lock-change-major-mode' to that hook. Of course, when this | |
241 | ;; hook is run, the major mode is in the process of being changed and we do not | |
242 | ;; know what the final major mode will be. So, `font-lock-change-major-mode' | |
243 | ;; only (a) notes the name of the current buffer, and (b) adds our function | |
35a46c5c | 244 | ;; `turn-on-font-lock-if-desired' to the hook variables |
21178fee LT |
245 | ;; `after-change-major-mode-hook' and `post-command-hook' (for modes |
246 | ;; that do not yet run `after-change-major-mode-hook'). By the time | |
f62be99b CW |
247 | ;; the functions on the first of these hooks to be run are run, the new major |
248 | ;; mode is assumed to be in place. This way we get a Font Lock function run | |
249 | ;; when a major mode is turned on, without knowing major modes or their hooks. | |
250 | ;; | |
21178fee LT |
251 | ;; Naturally this requires that major modes run `kill-all-local-variables' |
252 | ;; and `after-change-major-mode-hook', as they are supposed to. For modes | |
253 | ;; that do not run `after-change-major-mode-hook' yet, `post-command-hook' | |
254 | ;; takes care of things if the mode is set directly or indirectly by | |
255 | ;; an interactive command; however, problems can occur if the mode is | |
256 | ;; set by a timer or process: in that case, proper handling of Font Lock mode | |
257 | ;; may be delayed until the next interactive command. | |
f62be99b CW |
258 | |
259 | ;; User interface. | |
260 | ;; | |
261 | ;; Although Global Font Lock mode is a pseudo-mode, I think that the user | |
262 | ;; interface should conform to the usual Emacs convention for modes, i.e., a | |
263 | ;; command to toggle the feature (`global-font-lock-mode') with a variable for | |
fffa137c | 264 | ;; finer control of the mode's behavior (`font-lock-global-modes'). |
f62be99b CW |
265 | ;; |
266 | ;; The feature should not be enabled by loading font-lock.el, since other | |
267 | ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or | |
268 | ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be | |
269 | ;; turned on everywhere. That would not be intuitive or informative because | |
270 | ;; loading a file tells you nothing about the feature or how to control it. It | |
271 | ;; would also be contrary to the Principle of Least Surprise. sm. | |
272 | ||
273 | (defcustom font-lock-global-modes t | |
9201cc28 | 274 | "Modes for which Font Lock mode is automagically turned on. |
f62be99b CW |
275 | Global Font Lock mode is controlled by the command `global-font-lock-mode'. |
276 | If nil, means no modes have Font Lock mode automatically turned on. | |
277 | If t, all modes that support Font Lock mode have it automatically turned on. | |
278 | If a list, it should be a list of `major-mode' symbol names for which Font Lock | |
279 | mode should be automatically turned on. The sense of the list is negated if it | |
280 | begins with `not'. For example: | |
281 | (c-mode c++-mode) | |
282 | means that Font Lock mode is turned on for buffers in C and C++ modes only." | |
283 | :type '(choice (const :tag "none" nil) | |
284 | (const :tag "all" t) | |
285 | (set :menu-tag "mode specific" :tag "modes" | |
286 | :value (not) | |
287 | (const :tag "Except" not) | |
288 | (repeat :inline t (symbol :tag "mode")))) | |
289 | :group 'font-lock) | |
290 | ||
35a46c5c RS |
291 | (defun turn-on-font-lock-if-desired () |
292 | (when (cond ((eq font-lock-global-modes t) | |
293 | t) | |
294 | ((eq (car-safe font-lock-global-modes) 'not) | |
295 | (not (memq major-mode (cdr font-lock-global-modes)))) | |
347437a5 | 296 | (t (memq major-mode font-lock-global-modes))) |
f62be99b CW |
297 | (let (inhibit-quit) |
298 | (turn-on-font-lock)))) | |
299 | ||
44cba17e | 300 | (define-globalized-minor-mode global-font-lock-mode |
35a46c5c | 301 | font-lock-mode turn-on-font-lock-if-desired |
3ff522d9 JL |
302 | :extra-args (dummy) |
303 | :initialize 'custom-initialize-safe-default | |
304 | :init-value (not (or noninteractive emacs-basic-display)) | |
305 | :group 'font-lock | |
306 | :version "22.1") | |
f62be99b CW |
307 | |
308 | ;;; End of Global Font Lock mode. | |
309 | ||
310 | (provide 'font-core) | |
311 | ||
30b940a7 | 312 | ;; arch-tag: f8c286e1-02f7-41d9-b89b-1b67780aed71 |
f62be99b | 313 | ;;; font-core.el ends here |