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1 | ;;; font-core.el --- Core interface to font-lock |
2 | ||
ebd872c8 | 3 | ;; Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 1999, 2000, 2001, 02, 2003 |
f62be99b CW |
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 | ||
28 | ;; This variable is used by mode packages that support Font Lock mode by | |
29 | ;; defining their own keywords to use for `font-lock-keywords'. (The mode | |
30 | ;; command should make it buffer-local and set it to provide the set up.) | |
31 | (defvar font-lock-defaults nil | |
32 | "Defaults for Font Lock mode specified by the major mode. | |
33 | Defaults should be of the form: | |
34 | ||
35 | (KEYWORDS KEYWORDS-ONLY CASE-FOLD SYNTAX-ALIST SYNTAX-BEGIN ...) | |
36 | ||
37 | KEYWORDS may be a symbol (a variable or function whose value is the keywords to | |
38 | use for fontification) or a list of symbols. If KEYWORDS-ONLY is non-nil, | |
39 | syntactic fontification (strings and comments) is not performed. | |
40 | If CASE-FOLD is non-nil, the case of the keywords is ignored when fontifying. | |
41 | If SYNTAX-ALIST is non-nil, it should be a list of cons pairs of the form | |
42 | \(CHAR-OR-STRING . STRING) used to set the local Font Lock syntax table, for | |
43 | keyword and syntactic fontification (see `modify-syntax-entry'). | |
44 | ||
45 | If SYNTAX-BEGIN is non-nil, it should be a function with no args used to move | |
46 | backwards outside any enclosing syntactic block, for syntactic fontification. | |
47 | Typical values are `beginning-of-line' (i.e., the start of the line is known to | |
48 | be outside a syntactic block), or `beginning-of-defun' for programming modes or | |
49 | `backward-paragraph' for textual modes (i.e., the mode-dependent function is | |
50 | known to move outside a syntactic block). If nil, the beginning of the buffer | |
51 | is used as a position outside of a syntactic block, in the worst case. | |
52 | ||
53 | These item elements are used by Font Lock mode to set the variables | |
54 | `font-lock-keywords', `font-lock-keywords-only', | |
55 | `font-lock-keywords-case-fold-search', `font-lock-syntax-table' and | |
56 | `font-lock-beginning-of-syntax-function', respectively. | |
57 | ||
58 | Further item elements are alists of the form (VARIABLE . VALUE) and are in no | |
59 | particular order. Each VARIABLE is made buffer-local before set to VALUE. | |
60 | ||
61 | Currently, appropriate variables include `font-lock-mark-block-function'. | |
62 | If this is non-nil, it should be a function with no args used to mark any | |
63 | enclosing block of text, for fontification via \\[font-lock-fontify-block]. | |
64 | Typical values are `mark-defun' for programming modes or `mark-paragraph' for | |
65 | textual modes (i.e., the mode-dependent function is known to put point and mark | |
66 | around a text block relevant to that mode). | |
67 | ||
68 | Other variables include that for syntactic keyword fontification, | |
69 | `font-lock-syntactic-keywords' | |
f7abda1e | 70 | and those for buffer-specialized fontification functions, |
f62be99b CW |
71 | `font-lock-fontify-buffer-function', `font-lock-unfontify-buffer-function', |
72 | `font-lock-fontify-region-function', `font-lock-unfontify-region-function', | |
73 | `font-lock-inhibit-thing-lock' and `font-lock-maximum-size'.") | |
74 | (make-variable-buffer-local 'font-lock-defaults) | |
75 | ||
ebd872c8 | 76 | (defvar font-lock-defaults-alist nil |
f62be99b CW |
77 | "Alist of fall-back Font Lock defaults for major modes. |
78 | ||
f62be99b CW |
79 | Each item should be a list of the form: |
80 | ||
81 | (MAJOR-MODE . FONT-LOCK-DEFAULTS) | |
82 | ||
83 | where MAJOR-MODE is a symbol and FONT-LOCK-DEFAULTS is a list of default | |
84 | settings. See the variable `font-lock-defaults', which takes precedence.") | |
85 | (make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults) | |
86 | ||
7c4ef9b3 CW |
87 | (defvar font-lock-function 'font-lock-default-function |
88 | "A function which is called when `font-lock-mode' is toggled. | |
89 | It will be passed one argument, which is the current value of | |
90 | `font-lock-mode'.") | |
7c4ef9b3 | 91 | |
f62be99b CW |
92 | (define-minor-mode font-lock-mode |
93 | "Toggle Font Lock mode. | |
94 | With arg, turn Font Lock mode off if and only if arg is a non-positive | |
95 | number; if arg is nil, toggle Font Lock mode; anything else turns Font | |
96 | Lock on. | |
97 | \(Font Lock is also known as \"syntax highlighting\".) | |
98 | ||
99 | When Font Lock mode is enabled, text is fontified as you type it: | |
100 | ||
101 | - Comments are displayed in `font-lock-comment-face'; | |
102 | - Strings are displayed in `font-lock-string-face'; | |
103 | - Certain other expressions are displayed in other faces according to the | |
104 | value of the variable `font-lock-keywords'. | |
105 | ||
106 | To customize the faces (colors, fonts, etc.) used by Font Lock for | |
107 | fontifying different parts of buffer text, use \\[customize-face]. | |
108 | ||
109 | You can enable Font Lock mode in any major mode automatically by turning on in | |
110 | the major mode's hook. For example, put in your ~/.emacs: | |
111 | ||
112 | (add-hook 'c-mode-hook 'turn-on-font-lock) | |
113 | ||
114 | Alternatively, you can use Global Font Lock mode to automagically turn on Font | |
115 | Lock mode in buffers whose major mode supports it and whose major mode is one | |
116 | of `font-lock-global-modes'. For example, put in your ~/.emacs: | |
117 | ||
118 | (global-font-lock-mode t) | |
119 | ||
120 | There are a number of support modes that may be used to speed up Font Lock mode | |
121 | in various ways, specified via the variable `font-lock-support-mode'. Where | |
122 | major modes support different levels of fontification, you can use the variable | |
123 | `font-lock-maximum-decoration' to specify which level you generally prefer. | |
124 | When you turn Font Lock mode on/off the buffer is fontified/defontified, though | |
125 | fontification occurs only if the buffer is less than `font-lock-maximum-size'. | |
126 | ||
127 | For example, to specify that Font Lock mode use use Lazy Lock mode as a support | |
128 | mode and use maximum levels of fontification, put in your ~/.emacs: | |
129 | ||
130 | (setq font-lock-support-mode 'lazy-lock-mode) | |
131 | (setq font-lock-maximum-decoration t) | |
132 | ||
133 | To add your own highlighting for some major mode, and modify the highlighting | |
134 | selected automatically via the variable `font-lock-maximum-decoration', you can | |
135 | use `font-lock-add-keywords'. | |
136 | ||
137 | To fontify a buffer, without turning on Font Lock mode and regardless of buffer | |
138 | size, you can use \\[font-lock-fontify-buffer]. | |
139 | ||
140 | To fontify a block (the function or paragraph containing point, or a number of | |
141 | lines around point), perhaps because modification on the current line caused | |
142 | syntactic change on other lines, you can use \\[font-lock-fontify-block]. | |
143 | ||
144 | See the variable `font-lock-defaults-alist' for the Font Lock mode default | |
145 | settings. You can set your own default settings for some mode, by setting a | |
7c4ef9b3 CW |
146 | buffer local value for `font-lock-defaults', via its mode hook. |
147 | ||
148 | The above is the default behavior of `font-lock-mode'; you may specify | |
149 | your own function which is called when `font-lock-mode' is toggled via | |
150 | `font-lock-function'. " | |
f62be99b CW |
151 | nil nil nil |
152 | ;; Don't turn on Font Lock mode if we don't have a display (we're running a | |
153 | ;; batch job) or if the buffer is invisible (the name starts with a space). | |
154 | (when (or noninteractive (eq (aref (buffer-name) 0) ?\ )) | |
155 | (setq font-lock-mode nil)) | |
8e97108f RS |
156 | (funcall font-lock-function font-lock-mode) |
157 | ;; Arrange to unfontify this buffer if we change major mode later. | |
158 | (if font-lock-mode | |
2dc20ca8 RS |
159 | (add-hook 'change-major-mode-hook 'font-lock-change-mode nil t) |
160 | (remove-hook 'change-major-mode-hook 'font-lock-change-mode t))) | |
161 | ||
162 | ;; Get rid of fontification for the old major mode. | |
163 | ;; We do this when changing major modes. | |
164 | (defun font-lock-change-mode () | |
40e2bbe9 SM |
165 | (font-lock-mode -1)) |
166 | ||
67c9f58d RS |
167 | (defun font-lock-defontify () |
168 | "Clear out all `font-lock-face' properties in current buffer. | |
e350babd | 169 | A major mode that uses `font-lock-face' properties might want to put |
67c9f58d RS |
170 | this function onto `change-major-mode-hook'." |
171 | (let ((modp (buffer-modified-p)) | |
172 | (inhibit-read-only t)) | |
173 | (save-restriction | |
174 | (widen) | |
175 | (remove-list-of-text-properties (point-min) (point-max) | |
176 | '(font-lock-face))) | |
bb125ff0 | 177 | (restore-buffer-modified-p modp))) |
67c9f58d | 178 | |
40e2bbe9 | 179 | (defun font-lock-default-function (mode) |
f62be99b | 180 | ;; Turn on Font Lock mode. |
40e2bbe9 | 181 | (when mode |
1b6adddb CW |
182 | (set (make-local-variable 'char-property-alias-alist) |
183 | (copy-tree char-property-alias-alist)) | |
184 | ;; Add `font-lock-face' as an alias for the `face' property. | |
185 | (let ((elt (assq 'face char-property-alias-alist))) | |
186 | (if elt | |
187 | (unless (memq 'font-lock-face (cdr elt)) | |
188 | (setcdr elt (nconc (cdr elt) (list 'font-lock-face)))) | |
e350babd | 189 | (push (list 'face 'font-lock-face) char-property-alias-alist)))) |
f62be99b | 190 | ;; Turn off Font Lock mode. |
40e2bbe9 | 191 | (unless mode |
1b6adddb CW |
192 | ;; Remove `font-lock-face' as an alias for the `face' property. |
193 | (set (make-local-variable 'char-property-alias-alist) | |
194 | (copy-tree char-property-alias-alist)) | |
195 | (let ((elt (assq 'face char-property-alias-alist))) | |
196 | (when elt | |
197 | (setcdr elt (remq 'font-lock-face (cdr elt))) | |
198 | (when (null (cdr elt)) | |
e350babd SM |
199 | (setq char-property-alias-alist |
200 | (delq elt char-property-alias-alist)))))) | |
201 | ||
202 | ;; Only do hard work if the mode has specified stuff in | |
203 | ;; `font-lock-defaults'. | |
204 | (when (or font-lock-defaults | |
205 | (cdr (assq major-mode font-lock-defaults-alist))) | |
206 | (font-lock-mode-internal mode))) | |
71296446 | 207 | |
f62be99b CW |
208 | (defun turn-on-font-lock () |
209 | "Turn on Font Lock mode (only if the terminal can display it)." | |
210 | (unless font-lock-mode | |
211 | (font-lock-mode))) | |
212 | ||
f62be99b CW |
213 | ;;; Global Font Lock mode. |
214 | ||
215 | ;; A few people have hassled in the past for a way to make it easier to turn on | |
216 | ;; Font Lock mode, without the user needing to know for which modes s/he has to | |
217 | ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always | |
218 | ;; balked at that way, as I see it as just re-moulding the same problem in | |
219 | ;; another form. That is; some person would still have to keep track of which | |
220 | ;; modes (which may not even be distributed with Emacs) support Font Lock mode. | |
221 | ;; The list would always be out of date. And that person might have to be me. | |
222 | ||
223 | ;; Implementation. | |
224 | ;; | |
225 | ;; In a previous discussion the following hack came to mind. It is a gross | |
226 | ;; hack, but it generally works. We use the convention that major modes start | |
227 | ;; by calling the function `kill-all-local-variables', which in turn runs | |
228 | ;; functions on the hook variable `change-major-mode-hook'. We attach our | |
229 | ;; function `font-lock-change-major-mode' to that hook. Of course, when this | |
230 | ;; hook is run, the major mode is in the process of being changed and we do not | |
231 | ;; know what the final major mode will be. So, `font-lock-change-major-mode' | |
232 | ;; only (a) notes the name of the current buffer, and (b) adds our function | |
1a4914f3 | 233 | ;; `turn-on-font-lock-if-enabled' to the hook variables `find-file-hook' and |
f62be99b CW |
234 | ;; `post-command-hook' (for buffers that are not visiting files). By the time |
235 | ;; the functions on the first of these hooks to be run are run, the new major | |
236 | ;; mode is assumed to be in place. This way we get a Font Lock function run | |
237 | ;; when a major mode is turned on, without knowing major modes or their hooks. | |
238 | ;; | |
239 | ;; Naturally this requires that (a) major modes run `kill-all-local-variables', | |
240 | ;; as they are supposed to do, and (b) the major mode is in place after the | |
241 | ;; file is visited or the command that ran `kill-all-local-variables' has | |
242 | ;; finished, whichever the sooner. Arguably, any major mode that does not | |
243 | ;; follow the convension (a) is broken, and I can't think of any reason why (b) | |
244 | ;; would not be met (except `gnudoit' on non-files). However, it is not clean. | |
245 | ;; | |
246 | ;; Probably the cleanest solution is to have each major mode function run some | |
247 | ;; hook, e.g., `major-mode-hook', but maybe implementing that change is | |
248 | ;; impractical. I am personally against making `setq' a macro or be advised, | |
249 | ;; or have a special function such as `set-major-mode', but maybe someone can | |
250 | ;; come up with another solution? | |
251 | ||
252 | ;; User interface. | |
253 | ;; | |
254 | ;; Although Global Font Lock mode is a pseudo-mode, I think that the user | |
255 | ;; interface should conform to the usual Emacs convention for modes, i.e., a | |
256 | ;; command to toggle the feature (`global-font-lock-mode') with a variable for | |
257 | ;; finer control of the mode's behaviour (`font-lock-global-modes'). | |
258 | ;; | |
259 | ;; The feature should not be enabled by loading font-lock.el, since other | |
260 | ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or | |
261 | ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be | |
262 | ;; turned on everywhere. That would not be intuitive or informative because | |
263 | ;; loading a file tells you nothing about the feature or how to control it. It | |
264 | ;; would also be contrary to the Principle of Least Surprise. sm. | |
265 | ||
266 | (defcustom font-lock-global-modes t | |
267 | "*Modes for which Font Lock mode is automagically turned on. | |
268 | Global Font Lock mode is controlled by the command `global-font-lock-mode'. | |
269 | If nil, means no modes have Font Lock mode automatically turned on. | |
270 | If t, all modes that support Font Lock mode have it automatically turned on. | |
271 | If a list, it should be a list of `major-mode' symbol names for which Font Lock | |
272 | mode should be automatically turned on. The sense of the list is negated if it | |
273 | begins with `not'. For example: | |
274 | (c-mode c++-mode) | |
275 | means that Font Lock mode is turned on for buffers in C and C++ modes only." | |
276 | :type '(choice (const :tag "none" nil) | |
277 | (const :tag "all" t) | |
278 | (set :menu-tag "mode specific" :tag "modes" | |
279 | :value (not) | |
280 | (const :tag "Except" not) | |
281 | (repeat :inline t (symbol :tag "mode")))) | |
282 | :group 'font-lock) | |
283 | ||
284 | (defun turn-on-font-lock-if-enabled () | |
61fd2c68 CW |
285 | (unless (and (eq (car-safe font-lock-global-modes) 'not) |
286 | (memq major-mode (cdr font-lock-global-modes))) | |
f62be99b CW |
287 | (let (inhibit-quit) |
288 | (turn-on-font-lock)))) | |
289 | ||
290 | (easy-mmode-define-global-mode | |
291 | global-font-lock-mode font-lock-mode turn-on-font-lock-if-enabled | |
292 | :extra-args (dummy)) | |
293 | ||
294 | ;;; End of Global Font Lock mode. | |
295 | ||
296 | (provide 'font-core) | |
297 | ||
298 | ;;; font-core.el ends here | |
299 | ||
ab5796a9 | 300 | ;;; arch-tag: f8c286e1-02f7-41d9-b89b-1b67780aed71 |