;;; font-core.el --- Core interface to font-lock ;; Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 1999, 2000, 2001, 2002 ;; Free Software Foundation, Inc. ;; Maintainer: FSF ;; Keywords: languages, faces ;; This file is part of GNU Emacs. ;; GNU Emacs is free software; you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation; either version 2, or (at your option) ;; any later version. ;; GNU Emacs is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; You should have received a copy of the GNU General Public License ;; along with GNU Emacs; see the file COPYING. If not, write to the ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, ;; Boston, MA 02111-1307, USA. ;;; Code: ;; This variable is used by mode packages that support Font Lock mode by ;; defining their own keywords to use for `font-lock-keywords'. (The mode ;; command should make it buffer-local and set it to provide the set up.) (defvar font-lock-defaults nil "Defaults for Font Lock mode specified by the major mode. Defaults should be of the form: (KEYWORDS KEYWORDS-ONLY CASE-FOLD SYNTAX-ALIST SYNTAX-BEGIN ...) KEYWORDS may be a symbol (a variable or function whose value is the keywords to use for fontification) or a list of symbols. If KEYWORDS-ONLY is non-nil, syntactic fontification (strings and comments) is not performed. If CASE-FOLD is non-nil, the case of the keywords is ignored when fontifying. If SYNTAX-ALIST is non-nil, it should be a list of cons pairs of the form \(CHAR-OR-STRING . STRING) used to set the local Font Lock syntax table, for keyword and syntactic fontification (see `modify-syntax-entry'). If SYNTAX-BEGIN is non-nil, it should be a function with no args used to move backwards outside any enclosing syntactic block, for syntactic fontification. Typical values are `beginning-of-line' (i.e., the start of the line is known to be outside a syntactic block), or `beginning-of-defun' for programming modes or `backward-paragraph' for textual modes (i.e., the mode-dependent function is known to move outside a syntactic block). If nil, the beginning of the buffer is used as a position outside of a syntactic block, in the worst case. These item elements are used by Font Lock mode to set the variables `font-lock-keywords', `font-lock-keywords-only', `font-lock-keywords-case-fold-search', `font-lock-syntax-table' and `font-lock-beginning-of-syntax-function', respectively. Further item elements are alists of the form (VARIABLE . VALUE) and are in no particular order. Each VARIABLE is made buffer-local before set to VALUE. Currently, appropriate variables include `font-lock-mark-block-function'. If this is non-nil, it should be a function with no args used to mark any enclosing block of text, for fontification via \\[font-lock-fontify-block]. Typical values are `mark-defun' for programming modes or `mark-paragraph' for textual modes (i.e., the mode-dependent function is known to put point and mark around a text block relevant to that mode). Other variables include that for syntactic keyword fontification, `font-lock-syntactic-keywords' and those for buffer-specialised fontification functions, `font-lock-fontify-buffer-function', `font-lock-unfontify-buffer-function', `font-lock-fontify-region-function', `font-lock-unfontify-region-function', `font-lock-inhibit-thing-lock' and `font-lock-maximum-size'.") (make-variable-buffer-local 'font-lock-defaults) ;; This variable is used where font-lock.el itself supplies the ;; keywords. Really, this shouldn't need to be in font-core.el, but ;; we can't avoid it. In the future, this stuff will hopefully be ;; moved to cc-mode itself. (defvar font-lock-defaults-alist (let (;; We use `beginning-of-defun', rather than nil, for SYNTAX-BEGIN. ;; Thus the calculation of the cache is usually faster but not ;; infallible, so we risk mis-fontification. sm. (c-mode-defaults '((c-font-lock-keywords c-font-lock-keywords-1 c-font-lock-keywords-2 c-font-lock-keywords-3) nil nil ((?_ . "w")) beginning-of-defun (font-lock-syntactic-face-function . c-font-lock-syntactic-face-function) (font-lock-mark-block-function . mark-defun))) (c++-mode-defaults '((c++-font-lock-keywords c++-font-lock-keywords-1 c++-font-lock-keywords-2 c++-font-lock-keywords-3) nil nil ((?_ . "w")) beginning-of-defun (font-lock-syntactic-face-function . c-font-lock-syntactic-face-function) (font-lock-mark-block-function . mark-defun))) (objc-mode-defaults '((objc-font-lock-keywords objc-font-lock-keywords-1 objc-font-lock-keywords-2 objc-font-lock-keywords-3) nil nil ((?_ . "w") (?$ . "w")) nil (font-lock-syntactic-face-function . c-font-lock-syntactic-face-function) (font-lock-mark-block-function . mark-defun))) (java-mode-defaults '((java-font-lock-keywords java-font-lock-keywords-1 java-font-lock-keywords-2 java-font-lock-keywords-3) nil nil ((?_ . "w") (?$ . "w")) nil (font-lock-syntactic-face-function . java-font-lock-syntactic-face-function) (font-lock-mark-block-function . mark-defun)))) (list (cons 'c-mode c-mode-defaults) (cons 'c++-mode c++-mode-defaults) (cons 'objc-mode objc-mode-defaults) (cons 'java-mode java-mode-defaults))) "Alist of fall-back Font Lock defaults for major modes. This variable should not be used any more. Set the buffer-local `font-lock-keywords' in the major mode instead. Each item should be a list of the form: (MAJOR-MODE . FONT-LOCK-DEFAULTS) where MAJOR-MODE is a symbol and FONT-LOCK-DEFAULTS is a list of default settings. See the variable `font-lock-defaults', which takes precedence.") (make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults) (defvar font-lock-multiline nil "Whether font-lock should cater to multiline keywords. If nil, don't try to handle multiline patterns. If t, always handle multiline patterns. If `undecided', don't try to handle multiline patterns until you see one. Major/minor modes can set this variable if they know which option applies.") (defvar font-lock-fontified nil) ; Whether we have fontified the buffer. (defvar font-lock-category-alist nil "An alist of (CATEGORY-SYMBOL . FACE-PROP) controlled by Font Lock. This variable is intended to be used by special modes which construct buffer text for display to the user (i.e. buffer-menu, occur), but wish to have fontification turned on and off by Font Lock. If this variable is non-nil, then calling `font-lock-mode' will simply toggle the symbol property `face' of CATEGORY-SYMBOL.") (define-minor-mode font-lock-mode "Toggle Font Lock mode. With arg, turn Font Lock mode off if and only if arg is a non-positive number; if arg is nil, toggle Font Lock mode; anything else turns Font Lock on. \(Font Lock is also known as \"syntax highlighting\".) When Font Lock mode is enabled, text is fontified as you type it: - Comments are displayed in `font-lock-comment-face'; - Strings are displayed in `font-lock-string-face'; - Certain other expressions are displayed in other faces according to the value of the variable `font-lock-keywords'. To customize the faces (colors, fonts, etc.) used by Font Lock for fontifying different parts of buffer text, use \\[customize-face]. You can enable Font Lock mode in any major mode automatically by turning on in the major mode's hook. For example, put in your ~/.emacs: (add-hook 'c-mode-hook 'turn-on-font-lock) Alternatively, you can use Global Font Lock mode to automagically turn on Font Lock mode in buffers whose major mode supports it and whose major mode is one of `font-lock-global-modes'. For example, put in your ~/.emacs: (global-font-lock-mode t) There are a number of support modes that may be used to speed up Font Lock mode in various ways, specified via the variable `font-lock-support-mode'. Where major modes support different levels of fontification, you can use the variable `font-lock-maximum-decoration' to specify which level you generally prefer. When you turn Font Lock mode on/off the buffer is fontified/defontified, though fontification occurs only if the buffer is less than `font-lock-maximum-size'. For example, to specify that Font Lock mode use use Lazy Lock mode as a support mode and use maximum levels of fontification, put in your ~/.emacs: (setq font-lock-support-mode 'lazy-lock-mode) (setq font-lock-maximum-decoration t) To add your own highlighting for some major mode, and modify the highlighting selected automatically via the variable `font-lock-maximum-decoration', you can use `font-lock-add-keywords'. To fontify a buffer, without turning on Font Lock mode and regardless of buffer size, you can use \\[font-lock-fontify-buffer]. To fontify a block (the function or paragraph containing point, or a number of lines around point), perhaps because modification on the current line caused syntactic change on other lines, you can use \\[font-lock-fontify-block]. See the variable `font-lock-defaults-alist' for the Font Lock mode default settings. You can set your own default settings for some mode, by setting a buffer local value for `font-lock-defaults', via its mode hook." nil nil nil ;; Don't turn on Font Lock mode if we don't have a display (we're running a ;; batch job) or if the buffer is invisible (the name starts with a space). (when (or noninteractive (eq (aref (buffer-name) 0) ?\ )) (setq font-lock-mode nil)) ;; Turn on Font Lock mode. (when font-lock-mode (font-lock-set-defaults) (dolist (elt font-lock-category-alist) (put (car elt) 'face (cdr elt))) (when font-lock-defaults (add-hook 'after-change-functions 'font-lock-after-change-function t t) (font-lock-turn-on-thing-lock) ;; Fontify the buffer if we have to. (let ((max-size (font-lock-value-in-major-mode font-lock-maximum-size))) (cond (font-lock-fontified nil) ((or (null max-size) (> max-size (buffer-size))) (font-lock-fontify-buffer)) (font-lock-verbose (message "Fontifying %s...buffer size greater than font-lock-maximum-size" (buffer-name))))))) ;; Turn off Font Lock mode. (unless font-lock-mode (dolist (elt font-lock-category-alist) (put (car elt) 'face nil)) (when font-lock-defaults (remove-hook 'after-change-functions 'font-lock-after-change-function t) (font-lock-unfontify-buffer) (font-lock-turn-off-thing-lock)))) (defun turn-on-font-lock () "Turn on Font Lock mode (only if the terminal can display it)." (unless font-lock-mode (font-lock-mode))) (defvar font-lock-set-defaults nil) ; Whether we have set up defaults. (defun font-lock-set-defaults () "Set fontification defaults appropriately for this mode. Sets various variables using `font-lock-defaults' (or, if nil, using `font-lock-defaults-alist') and `font-lock-maximum-decoration'." (unless font-lock-set-defaults (set (make-local-variable 'font-lock-set-defaults) t) (make-local-variable 'font-lock-fontified) (make-local-variable 'font-lock-multiline) ;; Detect if this is a simple mode, which doesn't use any ;; syntactic fontification functions. (when (or font-lock-defaults (assq major-mode font-lock-defaults-alist)) (require 'font-lock) (font-lock-set-defaults-1)))) ;;; Global Font Lock mode. ;; A few people have hassled in the past for a way to make it easier to turn on ;; Font Lock mode, without the user needing to know for which modes s/he has to ;; turn it on, perhaps the same way hilit19.el/hl319.el does. I've always ;; balked at that way, as I see it as just re-moulding the same problem in ;; another form. That is; some person would still have to keep track of which ;; modes (which may not even be distributed with Emacs) support Font Lock mode. ;; The list would always be out of date. And that person might have to be me. ;; Implementation. ;; ;; In a previous discussion the following hack came to mind. It is a gross ;; hack, but it generally works. We use the convention that major modes start ;; by calling the function `kill-all-local-variables', which in turn runs ;; functions on the hook variable `change-major-mode-hook'. We attach our ;; function `font-lock-change-major-mode' to that hook. Of course, when this ;; hook is run, the major mode is in the process of being changed and we do not ;; know what the final major mode will be. So, `font-lock-change-major-mode' ;; only (a) notes the name of the current buffer, and (b) adds our function ;; `turn-on-font-lock-if-enabled' to the hook variables `find-file-hooks' and ;; `post-command-hook' (for buffers that are not visiting files). By the time ;; the functions on the first of these hooks to be run are run, the new major ;; mode is assumed to be in place. This way we get a Font Lock function run ;; when a major mode is turned on, without knowing major modes or their hooks. ;; ;; Naturally this requires that (a) major modes run `kill-all-local-variables', ;; as they are supposed to do, and (b) the major mode is in place after the ;; file is visited or the command that ran `kill-all-local-variables' has ;; finished, whichever the sooner. Arguably, any major mode that does not ;; follow the convension (a) is broken, and I can't think of any reason why (b) ;; would not be met (except `gnudoit' on non-files). However, it is not clean. ;; ;; Probably the cleanest solution is to have each major mode function run some ;; hook, e.g., `major-mode-hook', but maybe implementing that change is ;; impractical. I am personally against making `setq' a macro or be advised, ;; or have a special function such as `set-major-mode', but maybe someone can ;; come up with another solution? ;; User interface. ;; ;; Although Global Font Lock mode is a pseudo-mode, I think that the user ;; interface should conform to the usual Emacs convention for modes, i.e., a ;; command to toggle the feature (`global-font-lock-mode') with a variable for ;; finer control of the mode's behaviour (`font-lock-global-modes'). ;; ;; The feature should not be enabled by loading font-lock.el, since other ;; mechanisms for turning on Font Lock mode, such as M-x font-lock-mode RET or ;; (add-hook 'c-mode-hook 'turn-on-font-lock), would cause Font Lock mode to be ;; turned on everywhere. That would not be intuitive or informative because ;; loading a file tells you nothing about the feature or how to control it. It ;; would also be contrary to the Principle of Least Surprise. sm. (defcustom font-lock-global-modes t "*Modes for which Font Lock mode is automagically turned on. Global Font Lock mode is controlled by the command `global-font-lock-mode'. If nil, means no modes have Font Lock mode automatically turned on. If t, all modes that support Font Lock mode have it automatically turned on. If a list, it should be a list of `major-mode' symbol names for which Font Lock mode should be automatically turned on. The sense of the list is negated if it begins with `not'. For example: (c-mode c++-mode) means that Font Lock mode is turned on for buffers in C and C++ modes only." :type '(choice (const :tag "none" nil) (const :tag "all" t) (set :menu-tag "mode specific" :tag "modes" :value (not) (const :tag "Except" not) (repeat :inline t (symbol :tag "mode")))) :group 'font-lock) (defun turn-on-font-lock-if-enabled () (when (and (or font-lock-defaults font-lock-category-alist (assq major-mode font-lock-defaults-alist)) (or (eq font-lock-global-modes t) (if (eq (car-safe font-lock-global-modes) 'not) (not (memq major-mode (cdr font-lock-global-modes))) (memq major-mode font-lock-global-modes)))) (let (inhibit-quit) (turn-on-font-lock)))) (easy-mmode-define-global-mode global-font-lock-mode font-lock-mode turn-on-font-lock-if-enabled :extra-args (dummy)) ;;; End of Global Font Lock mode. (provide 'font-core) ;;; font-core.el ends here