| 1 | ;;; font-core.el --- Core interface to font-lock |
| 2 | |
| 3 | ;; Copyright (C) 1992-2012 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Maintainer: FSF |
| 6 | ;; Keywords: languages, faces |
| 7 | ;; Package: emacs |
| 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 3 of the License, or |
| 14 | ;; (at your option) 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. If not, see <http://www.gnu.org/licenses/>. |
| 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 | |
| 33 | (KEYWORDS [KEYWORDS-ONLY [CASE-FOLD [SYNTAX-ALIST [SYNTAX-BEGIN ...]]]]) |
| 34 | |
| 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 | |
| 42 | If CASE-FOLD is non-nil, the case of the keywords is ignored when fontifying. |
| 43 | |
| 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 | \(See also Info node `(elisp)Font Lock Basics'.) |
| 57 | |
| 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, |
| 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'.") |
| 78 | ;;;###autoload |
| 79 | (put 'font-lock-defaults 'risky-local-variable t) |
| 80 | (make-variable-buffer-local 'font-lock-defaults) |
| 81 | |
| 82 | (defvar font-lock-function 'font-lock-default-function |
| 83 | "A function which is called when `font-lock-mode' is toggled. |
| 84 | It will be passed one argument, which is the current value of |
| 85 | `font-lock-mode'.") |
| 86 | |
| 87 | ;; The mode for which font-lock was initialized, or nil if none. |
| 88 | (defvar font-lock-major-mode) |
| 89 | |
| 90 | (define-minor-mode font-lock-mode |
| 91 | "Toggle syntax highlighting in this buffer (Font Lock mode). |
| 92 | With a prefix argument ARG, enable Font Lock mode if ARG is |
| 93 | positive, and disable it otherwise. If called from Lisp, enable |
| 94 | the mode if ARG is omitted or nil. |
| 95 | |
| 96 | When Font Lock mode is enabled, text is fontified as you type it: |
| 97 | |
| 98 | - Comments are displayed in `font-lock-comment-face'; |
| 99 | - Strings are displayed in `font-lock-string-face'; |
| 100 | - Certain other expressions are displayed in other faces according to the |
| 101 | value of the variable `font-lock-keywords'. |
| 102 | |
| 103 | To customize the faces (colors, fonts, etc.) used by Font Lock for |
| 104 | fontifying different parts of buffer text, use \\[customize-face]. |
| 105 | |
| 106 | You can enable Font Lock mode in any major mode automatically by turning on in |
| 107 | the major mode's hook. For example, put in your ~/.emacs: |
| 108 | |
| 109 | (add-hook 'c-mode-hook 'turn-on-font-lock) |
| 110 | |
| 111 | Alternatively, you can use Global Font Lock mode to automagically turn on Font |
| 112 | Lock mode in buffers whose major mode supports it and whose major mode is one |
| 113 | of `font-lock-global-modes'. For example, put in your ~/.emacs: |
| 114 | |
| 115 | (global-font-lock-mode t) |
| 116 | |
| 117 | Where major modes support different levels of fontification, you can use |
| 118 | the variable `font-lock-maximum-decoration' to specify which level you |
| 119 | generally prefer. When you turn Font Lock mode on/off the buffer is |
| 120 | fontified/defontified, though fontification occurs only if the buffer is |
| 121 | less than `font-lock-maximum-size'. |
| 122 | |
| 123 | To add your own highlighting for some major mode, and modify the highlighting |
| 124 | selected automatically via the variable `font-lock-maximum-decoration', you can |
| 125 | use `font-lock-add-keywords'. |
| 126 | |
| 127 | To fontify a buffer, without turning on Font Lock mode and regardless of buffer |
| 128 | size, you can use \\[font-lock-fontify-buffer]. |
| 129 | |
| 130 | To fontify a block (the function or paragraph containing point, or a number of |
| 131 | lines around point), perhaps because modification on the current line caused |
| 132 | syntactic change on other lines, you can use \\[font-lock-fontify-block]. |
| 133 | |
| 134 | You can set your own default settings for some mode, by setting a |
| 135 | buffer local value for `font-lock-defaults', via its mode hook. |
| 136 | |
| 137 | The above is the default behavior of `font-lock-mode'; you may specify |
| 138 | your own function which is called when `font-lock-mode' is toggled via |
| 139 | `font-lock-function'. " |
| 140 | nil nil nil |
| 141 | :after-hook (font-lock-initial-fontify) |
| 142 | ;; Don't turn on Font Lock mode if we don't have a display (we're running a |
| 143 | ;; batch job) or if the buffer is invisible (the name starts with a space). |
| 144 | (when (or noninteractive (eq (aref (buffer-name) 0) ?\s)) |
| 145 | (setq font-lock-mode nil)) |
| 146 | (funcall font-lock-function font-lock-mode) |
| 147 | ;; Arrange to unfontify this buffer if we change major mode later. |
| 148 | (if font-lock-mode |
| 149 | (add-hook 'change-major-mode-hook 'font-lock-change-mode nil t) |
| 150 | (remove-hook 'change-major-mode-hook 'font-lock-change-mode t))) |
| 151 | |
| 152 | ;; Get rid of fontification for the old major mode. |
| 153 | ;; We do this when changing major modes. |
| 154 | (defun font-lock-change-mode () |
| 155 | (font-lock-mode -1)) |
| 156 | |
| 157 | (defun font-lock-defontify () |
| 158 | "Clear out all `font-lock-face' properties in current buffer. |
| 159 | A major mode that uses `font-lock-face' properties might want to put |
| 160 | this function onto `change-major-mode-hook'." |
| 161 | (let ((modp (buffer-modified-p)) |
| 162 | (inhibit-read-only t)) |
| 163 | (save-restriction |
| 164 | (widen) |
| 165 | (remove-list-of-text-properties (point-min) (point-max) |
| 166 | '(font-lock-face))) |
| 167 | (restore-buffer-modified-p modp))) |
| 168 | |
| 169 | (defvar font-lock-set-defaults) |
| 170 | (defun font-lock-default-function (mode) |
| 171 | ;; Turn on Font Lock mode. |
| 172 | (when mode |
| 173 | (set (make-local-variable 'char-property-alias-alist) |
| 174 | (copy-tree char-property-alias-alist)) |
| 175 | ;; Add `font-lock-face' as an alias for the `face' property. |
| 176 | (let ((elt (assq 'face char-property-alias-alist))) |
| 177 | (if elt |
| 178 | (unless (memq 'font-lock-face (cdr elt)) |
| 179 | (setcdr elt (nconc (cdr elt) (list 'font-lock-face)))) |
| 180 | (push (list 'face 'font-lock-face) char-property-alias-alist)))) |
| 181 | ;; Turn off Font Lock mode. |
| 182 | (unless mode |
| 183 | ;; Remove `font-lock-face' as an alias for the `face' property. |
| 184 | (set (make-local-variable 'char-property-alias-alist) |
| 185 | (copy-tree char-property-alias-alist)) |
| 186 | (let ((elt (assq 'face char-property-alias-alist))) |
| 187 | (when elt |
| 188 | (setcdr elt (remq 'font-lock-face (cdr elt))) |
| 189 | (when (null (cdr elt)) |
| 190 | (setq char-property-alias-alist |
| 191 | (delq elt char-property-alias-alist)))))) |
| 192 | |
| 193 | ;; Only do hard work if the mode has specified stuff in |
| 194 | ;; `font-lock-defaults'. |
| 195 | (when (font-lock-specified-p mode) |
| 196 | (font-lock-mode-internal mode))) |
| 197 | |
| 198 | (defun turn-on-font-lock () |
| 199 | "Turn on Font Lock mode (only if the terminal can display it)." |
| 200 | (unless font-lock-mode |
| 201 | (font-lock-mode))) |
| 202 | |
| 203 | ;;; Global Font Lock mode. |
| 204 | |
| 205 | ;; A few people have hassled in the past for a way to make it easier to turn on |
| 206 | ;; Font Lock mode, without the user needing to know for which modes s/he has to |
| 207 | ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always |
| 208 | ;; balked at that way, as I see it as just re-molding the same problem in |
| 209 | ;; another form. That is; some person would still have to keep track of which |
| 210 | ;; modes (which may not even be distributed with Emacs) support Font Lock mode. |
| 211 | ;; The list would always be out of date. And that person might have to be me. |
| 212 | |
| 213 | ;; Implementation. |
| 214 | ;; |
| 215 | ;; In a previous discussion the following hack came to mind. It is a gross |
| 216 | ;; hack, but it generally works. We use the convention that major modes start |
| 217 | ;; by calling the function `kill-all-local-variables', which in turn runs |
| 218 | ;; functions on the hook variable `change-major-mode-hook'. We attach our |
| 219 | ;; function `font-lock-change-major-mode' to that hook. Of course, when this |
| 220 | ;; hook is run, the major mode is in the process of being changed and we do not |
| 221 | ;; know what the final major mode will be. So, `font-lock-change-major-mode' |
| 222 | ;; only (a) notes the name of the current buffer, and (b) adds our function |
| 223 | ;; `turn-on-font-lock-if-desired' to the hook variables |
| 224 | ;; `after-change-major-mode-hook' and `post-command-hook' (for modes |
| 225 | ;; that do not yet run `after-change-major-mode-hook'). By the time |
| 226 | ;; the functions on the first of these hooks to be run are run, the new major |
| 227 | ;; mode is assumed to be in place. This way we get a Font Lock function run |
| 228 | ;; when a major mode is turned on, without knowing major modes or their hooks. |
| 229 | ;; |
| 230 | ;; Naturally this requires that major modes run `kill-all-local-variables' |
| 231 | ;; and `after-change-major-mode-hook', as they are supposed to. For modes |
| 232 | ;; that do not run `after-change-major-mode-hook' yet, `post-command-hook' |
| 233 | ;; takes care of things if the mode is set directly or indirectly by |
| 234 | ;; an interactive command; however, problems can occur if the mode is |
| 235 | ;; set by a timer or process: in that case, proper handling of Font Lock mode |
| 236 | ;; may be delayed until the next interactive command. |
| 237 | |
| 238 | ;; User interface. |
| 239 | ;; |
| 240 | ;; Although Global Font Lock mode is a pseudo-mode, I think that the user |
| 241 | ;; interface should conform to the usual Emacs convention for modes, i.e., a |
| 242 | ;; command to toggle the feature (`global-font-lock-mode') with a variable for |
| 243 | ;; finer control of the mode's behavior (`font-lock-global-modes'). |
| 244 | ;; |
| 245 | ;; The feature should not be enabled by loading font-lock.el, since other |
| 246 | ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or |
| 247 | ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be |
| 248 | ;; turned on everywhere. That would not be intuitive or informative because |
| 249 | ;; loading a file tells you nothing about the feature or how to control it. It |
| 250 | ;; would also be contrary to the Principle of Least Surprise. sm. |
| 251 | |
| 252 | (defcustom font-lock-global-modes t |
| 253 | "Modes for which Font Lock mode is automagically turned on. |
| 254 | Global Font Lock mode is controlled by the command `global-font-lock-mode'. |
| 255 | If nil, means no modes have Font Lock mode automatically turned on. |
| 256 | If t, all modes that support Font Lock mode have it automatically turned on. |
| 257 | If a list, it should be a list of `major-mode' symbol names for which Font Lock |
| 258 | mode should be automatically turned on. The sense of the list is negated if it |
| 259 | begins with `not'. For example: |
| 260 | (c-mode c++-mode) |
| 261 | means that Font Lock mode is turned on for buffers in C and C++ modes only." |
| 262 | :type '(choice (const :tag "none" nil) |
| 263 | (const :tag "all" t) |
| 264 | (set :menu-tag "mode specific" :tag "modes" |
| 265 | :value (not) |
| 266 | (const :tag "Except" not) |
| 267 | (repeat :inline t (symbol :tag "mode")))) |
| 268 | :group 'font-lock) |
| 269 | |
| 270 | (defun turn-on-font-lock-if-desired () |
| 271 | (when (cond ((eq font-lock-global-modes t) |
| 272 | t) |
| 273 | ((eq (car-safe font-lock-global-modes) 'not) |
| 274 | (not (memq major-mode (cdr font-lock-global-modes)))) |
| 275 | (t (memq major-mode font-lock-global-modes))) |
| 276 | (let (inhibit-quit) |
| 277 | (turn-on-font-lock)))) |
| 278 | |
| 279 | (define-globalized-minor-mode global-font-lock-mode |
| 280 | font-lock-mode turn-on-font-lock-if-desired |
| 281 | ;; What was this :extra-args thingy for? --Stef |
| 282 | ;; :extra-args (dummy) |
| 283 | :initialize 'custom-initialize-delay |
| 284 | :init-value (not (or noninteractive emacs-basic-display)) |
| 285 | :group 'font-lock |
| 286 | :version "22.1") |
| 287 | |
| 288 | ;;; End of Global Font Lock mode. |
| 289 | |
| 290 | (provide 'font-core) |
| 291 | |
| 292 | ;;; font-core.el ends here |