1 ;;; font-core.el --- Core interface to font-lock
3 ;; Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 1999, 2000, 2001, 2002
4 ;; Free Software Foundation, Inc.
7 ;; Keywords: languages, faces
9 ;; This file is part of GNU Emacs.
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)
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.
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.
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:
35 (KEYWORDS KEYWORDS-ONLY CASE-FOLD SYNTAX-ALIST SYNTAX-BEGIN ...)
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').
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.
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.
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.
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).
68 Other variables include that for syntactic keyword fontification,
69 `font-lock-syntactic-keywords'
70 and those for buffer-specialised fontification functions,
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)
76 ;; This variable is used where font-lock.el itself supplies the
77 ;; keywords. Really, this shouldn't need to be in font-core.el, but
78 ;; we can't avoid it. In the future, this stuff will hopefully be
79 ;; moved to cc-mode itself.
80 (defvar font-lock-defaults-alist
81 (let (;; We use `beginning-of-defun', rather than nil, for SYNTAX-BEGIN.
82 ;; Thus the calculation of the cache is usually faster but not
83 ;; infallible, so we risk mis-fontification. sm.
85 '((c-font-lock-keywords c-font-lock-keywords-1
86 c-font-lock-keywords-2 c-font-lock-keywords-3)
87 nil nil ((?_ . "w")) beginning-of-defun
88 (font-lock-syntactic-face-function
89 . c-font-lock-syntactic-face-function)
90 (font-lock-mark-block-function . mark-defun)))
92 '((c++-font-lock-keywords c++-font-lock-keywords-1
93 c++-font-lock-keywords-2 c++-font-lock-keywords-3)
94 nil nil ((?_ . "w")) beginning-of-defun
95 (font-lock-syntactic-face-function
96 . c-font-lock-syntactic-face-function)
97 (font-lock-mark-block-function . mark-defun)))
99 '((objc-font-lock-keywords objc-font-lock-keywords-1
100 objc-font-lock-keywords-2 objc-font-lock-keywords-3)
101 nil nil ((?_ . "w") (?$ . "w")) nil
102 (font-lock-syntactic-face-function
103 . c-font-lock-syntactic-face-function)
104 (font-lock-mark-block-function . mark-defun)))
106 '((java-font-lock-keywords java-font-lock-keywords-1
107 java-font-lock-keywords-2 java-font-lock-keywords-3)
108 nil nil ((?_ . "w") (?$ . "w")) nil
109 (font-lock-syntactic-face-function
110 . java-font-lock-syntactic-face-function)
111 (font-lock-mark-block-function . mark-defun))))
113 (cons 'c-mode c-mode-defaults)
114 (cons 'c++-mode c++-mode-defaults)
115 (cons 'objc-mode objc-mode-defaults)
116 (cons 'java-mode java-mode-defaults)))
117 "Alist of fall-back Font Lock defaults for major modes.
119 This variable should not be used any more.
120 Set the buffer-local `font-lock-keywords' in the major mode instead.
122 Each item should be a list of the form:
124 (MAJOR-MODE . FONT-LOCK-DEFAULTS)
126 where MAJOR-MODE is a symbol and FONT-LOCK-DEFAULTS is a list of default
127 settings. See the variable `font-lock-defaults', which takes precedence.")
128 (make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults)
130 (defvar font-lock-multiline nil
131 "Whether font-lock should cater to multiline keywords.
132 If nil, don't try to handle multiline patterns.
133 If t, always handle multiline patterns.
134 If `undecided', don't try to handle multiline patterns until you see one.
135 Major/minor modes can set this variable if they know which option applies.")
137 (defvar font-lock-fontified nil) ; Whether we have fontified the buffer.
139 (defvar font-lock-function 'font-lock-default-function
140 "A function which is called when `font-lock-mode' is toggled.
141 It will be passed one argument, which is the current value of
143 (make-variable-buffer-local 'font-lock-default-function)
145 (define-minor-mode font-lock-mode
146 "Toggle Font Lock mode.
147 With arg, turn Font Lock mode off if and only if arg is a non-positive
148 number; if arg is nil, toggle Font Lock mode; anything else turns Font
150 \(Font Lock is also known as \"syntax highlighting\".)
152 When Font Lock mode is enabled, text is fontified as you type it:
154 - Comments are displayed in `font-lock-comment-face';
155 - Strings are displayed in `font-lock-string-face';
156 - Certain other expressions are displayed in other faces according to the
157 value of the variable `font-lock-keywords'.
159 To customize the faces (colors, fonts, etc.) used by Font Lock for
160 fontifying different parts of buffer text, use \\[customize-face].
162 You can enable Font Lock mode in any major mode automatically by turning on in
163 the major mode's hook. For example, put in your ~/.emacs:
165 (add-hook 'c-mode-hook 'turn-on-font-lock)
167 Alternatively, you can use Global Font Lock mode to automagically turn on Font
168 Lock mode in buffers whose major mode supports it and whose major mode is one
169 of `font-lock-global-modes'. For example, put in your ~/.emacs:
171 (global-font-lock-mode t)
173 There are a number of support modes that may be used to speed up Font Lock mode
174 in various ways, specified via the variable `font-lock-support-mode'. Where
175 major modes support different levels of fontification, you can use the variable
176 `font-lock-maximum-decoration' to specify which level you generally prefer.
177 When you turn Font Lock mode on/off the buffer is fontified/defontified, though
178 fontification occurs only if the buffer is less than `font-lock-maximum-size'.
180 For example, to specify that Font Lock mode use use Lazy Lock mode as a support
181 mode and use maximum levels of fontification, put in your ~/.emacs:
183 (setq font-lock-support-mode 'lazy-lock-mode)
184 (setq font-lock-maximum-decoration t)
186 To add your own highlighting for some major mode, and modify the highlighting
187 selected automatically via the variable `font-lock-maximum-decoration', you can
188 use `font-lock-add-keywords'.
190 To fontify a buffer, without turning on Font Lock mode and regardless of buffer
191 size, you can use \\[font-lock-fontify-buffer].
193 To fontify a block (the function or paragraph containing point, or a number of
194 lines around point), perhaps because modification on the current line caused
195 syntactic change on other lines, you can use \\[font-lock-fontify-block].
197 See the variable `font-lock-defaults-alist' for the Font Lock mode default
198 settings. You can set your own default settings for some mode, by setting a
199 buffer local value for `font-lock-defaults', via its mode hook.
201 The above is the default behavior of `font-lock-mode'; you may specify
202 your own function which is called when `font-lock-mode' is toggled via
203 `font-lock-function'. "
205 ;; Don't turn on Font Lock mode if we don't have a display (we're running a
206 ;; batch job) or if the buffer is invisible (the name starts with a space).
207 (when (or noninteractive (eq (aref (buffer-name) 0) ?\ ))
208 (setq font-lock-mode nil))
209 (funcall font-lock-function font-lock-mode))
211 (defun font-lock-default-function (font-lock-mode)
212 ;; Turn on Font Lock mode.
214 (font-lock-set-defaults)
215 (set (make-local-variable 'char-property-alias-alist)
216 (copy-tree char-property-alias-alist))
217 ;; Add `font-lock-face' as an alias for the `face' property.
218 (let ((elt (assq 'face char-property-alias-alist)))
220 (unless (memq 'font-lock-face (cdr elt))
221 (setcdr elt (nconc (cdr elt) (list 'font-lock-face))))
222 (push (list 'face 'font-lock-face) char-property-alias-alist)))
223 ;; Only do hard work if the mode has specified stuff in
224 ;; `font-lock-defaults'.
225 (when font-lock-defaults
226 (add-hook 'after-change-functions 'font-lock-after-change-function t t)
227 (font-lock-turn-on-thing-lock)
228 ;; Fontify the buffer if we have to.
229 (let ((max-size (font-lock-value-in-major-mode font-lock-maximum-size)))
230 (cond (font-lock-fontified
232 ((or (null max-size) (> max-size (buffer-size)))
233 (font-lock-fontify-buffer))
235 (message "Fontifying %s...buffer size greater than font-lock-maximum-size"
237 ;; Turn off Font Lock mode.
238 (unless font-lock-mode
239 ;; Remove `font-lock-face' as an alias for the `face' property.
240 (set (make-local-variable 'char-property-alias-alist)
241 (copy-tree char-property-alias-alist))
242 (let ((elt (assq 'face char-property-alias-alist)))
244 (setcdr elt (remq 'font-lock-face (cdr elt)))
245 (when (null (cdr elt))
246 (setq char-property-alias-alist (delq elt char-property-alias-alist)))))
247 (when font-lock-defaults
248 (remove-hook 'after-change-functions 'font-lock-after-change-function t)
249 (font-lock-unfontify-buffer)
250 (font-lock-turn-off-thing-lock))))
252 (defun turn-on-font-lock ()
253 "Turn on Font Lock mode (only if the terminal can display it)."
254 (unless font-lock-mode
257 (defvar font-lock-set-defaults nil) ; Whether we have set up defaults.
259 (defun font-lock-set-defaults ()
260 "Set fontification defaults appropriately for this mode.
261 Sets various variables using `font-lock-defaults' (or, if nil, using
262 `font-lock-defaults-alist') and `font-lock-maximum-decoration'."
263 (unless font-lock-set-defaults
264 (set (make-local-variable 'font-lock-set-defaults) t)
265 (make-local-variable 'font-lock-fontified)
266 (make-local-variable 'font-lock-multiline)
267 (let ((defaults (or font-lock-defaults
268 (cdr (assq major-mode font-lock-defaults-alist)))))
271 (font-lock-set-defaults-1)))))
273 ;;; Global Font Lock mode.
275 ;; A few people have hassled in the past for a way to make it easier to turn on
276 ;; Font Lock mode, without the user needing to know for which modes s/he has to
277 ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always
278 ;; balked at that way, as I see it as just re-moulding the same problem in
279 ;; another form. That is; some person would still have to keep track of which
280 ;; modes (which may not even be distributed with Emacs) support Font Lock mode.
281 ;; The list would always be out of date. And that person might have to be me.
285 ;; In a previous discussion the following hack came to mind. It is a gross
286 ;; hack, but it generally works. We use the convention that major modes start
287 ;; by calling the function `kill-all-local-variables', which in turn runs
288 ;; functions on the hook variable `change-major-mode-hook'. We attach our
289 ;; function `font-lock-change-major-mode' to that hook. Of course, when this
290 ;; hook is run, the major mode is in the process of being changed and we do not
291 ;; know what the final major mode will be. So, `font-lock-change-major-mode'
292 ;; only (a) notes the name of the current buffer, and (b) adds our function
293 ;; `turn-on-font-lock-if-enabled' to the hook variables `find-file-hooks' and
294 ;; `post-command-hook' (for buffers that are not visiting files). By the time
295 ;; the functions on the first of these hooks to be run are run, the new major
296 ;; mode is assumed to be in place. This way we get a Font Lock function run
297 ;; when a major mode is turned on, without knowing major modes or their hooks.
299 ;; Naturally this requires that (a) major modes run `kill-all-local-variables',
300 ;; as they are supposed to do, and (b) the major mode is in place after the
301 ;; file is visited or the command that ran `kill-all-local-variables' has
302 ;; finished, whichever the sooner. Arguably, any major mode that does not
303 ;; follow the convension (a) is broken, and I can't think of any reason why (b)
304 ;; would not be met (except `gnudoit' on non-files). However, it is not clean.
306 ;; Probably the cleanest solution is to have each major mode function run some
307 ;; hook, e.g., `major-mode-hook', but maybe implementing that change is
308 ;; impractical. I am personally against making `setq' a macro or be advised,
309 ;; or have a special function such as `set-major-mode', but maybe someone can
310 ;; come up with another solution?
314 ;; Although Global Font Lock mode is a pseudo-mode, I think that the user
315 ;; interface should conform to the usual Emacs convention for modes, i.e., a
316 ;; command to toggle the feature (`global-font-lock-mode') with a variable for
317 ;; finer control of the mode's behaviour (`font-lock-global-modes').
319 ;; The feature should not be enabled by loading font-lock.el, since other
320 ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or
321 ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be
322 ;; turned on everywhere. That would not be intuitive or informative because
323 ;; loading a file tells you nothing about the feature or how to control it. It
324 ;; would also be contrary to the Principle of Least Surprise. sm.
326 (defcustom font-lock-global-modes t
327 "*Modes for which Font Lock mode is automagically turned on.
328 Global Font Lock mode is controlled by the command `global-font-lock-mode'.
329 If nil, means no modes have Font Lock mode automatically turned on.
330 If t, all modes that support Font Lock mode have it automatically turned on.
331 If a list, it should be a list of `major-mode' symbol names for which Font Lock
332 mode should be automatically turned on. The sense of the list is negated if it
333 begins with `not'. For example:
335 means that Font Lock mode is turned on for buffers in C and C++ modes only."
336 :type '(choice (const :tag "none" nil)
338 (set :menu-tag "mode specific" :tag "modes"
340 (const :tag "Except" not)
341 (repeat :inline t (symbol :tag "mode"))))
344 (defun turn-on-font-lock-if-enabled ()
345 (unless (and (eq (car-safe font-lock-global-modes) 'not)
346 (memq major-mode (cdr font-lock-global-modes)))
348 (turn-on-font-lock))))
350 (easy-mmode-define-global-mode
351 global-font-lock-mode font-lock-mode turn-on-font-lock-if-enabled
354 ;;; End of Global Font Lock mode.
358 ;;; font-core.el ends here