-;;; syntax.el --- helper functions to find syntactic context
-
-;; Copyright (C) 2000 Free Software Foundation, Inc.
-
-;; Maintainer: FSF
-;; Keywords: internal
-
-;; 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.
-
-;;; Commentary:
-
-;; The main exported function is `syntax-ppss'. You might also need
-;; to call `syntax-ppss-after-change-function' or to add it to
-;; after-change-functions'(although this is automatically done by
-;; syntax-ppss when needed, but that might fail if syntax-ppss is
-;; called in a context where after-change-functions is temporarily
-;; let-bound to nil).
-
-;;; Todo:
-
-;; - do something about the case where the syntax-table is changed.
-;; This typically happens with tex-mode and its `$' operator.
-;; - move font-lock-syntactic-keywords in here. Then again, maybe not.
-;; - new functions `syntax-state', ... to replace uses of parse-partial-state
-;; with something higher-level (similar to syntax-ppss-context).
-;; - interaction with mmm-mode.
-;; - what to do when the buffer is narrowed ?
-
-;;; Code:
-
-;; Note: PPSS stands for `parse-partial-sexp state'
-
-(eval-when-compile (require 'cl))
-
-(defsubst syntax-ppss-depth (ppss)
- (nth 0 ppss))
-
-(defsubst syntax-ppss-context (ppss)
- (cond
- ((nth 3 ppss) 'string)
- ((nth 4 ppss) 'comment)
- (t nil)))
-
-(defvar syntax-ppss-max-span 20000
- "Threshold below which cache info is deemed unnecessary.
-We try to make sure that cache entries are at least this far apart
-from each other, to avoid keeping too much useless info.")
-
-(defvar syntax-begin-function nil
- "Function to move back outside of any comment/string/paren.
-This function should move the cursor back to some syntactically safe
-point (where the PPSS is equivalent to nil).")
-
-(defvar syntax-ppss-cache nil
- "List of (POS . PPSS) pairs, in decreasing POS order.")
-(make-variable-buffer-local 'syntax-ppss-cache)
-(defvar syntax-ppss-last nil
- "Cache of (LAST-POS . LAST-PPSS).")
-(make-variable-buffer-local 'syntax-ppss-last)
-
-(defun syntax-ppss-after-change-function (beg &rest ignored)
- ;; Flush invalid cache entries.
- (while (and syntax-ppss-cache (> (caar syntax-ppss-cache) beg))
- (setq syntax-ppss-cache (cdr syntax-ppss-cache)))
- ;; Throw away `last' value if made invalid.
- (when (< beg (or (car syntax-ppss-last) 0))
- (if (< beg (or (car (nth 10 syntax-ppss-last))
- (nth 9 syntax-ppss-last)
- (nth 2 syntax-ppss-last)
- 0))
- (setq syntax-ppss-last nil)
- (setcar syntax-ppss-last nil)))
- ;; Unregister if there's no cache left. Sadly this doesn't work
- ;; because `after-change-functions' is temporarily bound to nil here.
- ;; (unless syntax-ppss-cache
- ;; (remove-hook 'after-change-functions
- ;; 'syntax-ppss-after-change-function t))
- )
-
-(defvar syntax-ppss-stats
- [(0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (1 . 2500.0)])
-(defun syntax-ppss-stats ()
- (mapcar (lambda (x)
- (condition-case nil
- (cons (car x) (truncate (/ (cdr x) (car x))))
- (error nil)))
- syntax-ppss-stats))
-
-;;;###autoload
-(defun syntax-ppss (&optional pos)
- "Parse-Partial-Sexp State at POS.
-The returned value is the same as `parse-partial-sexp' except that
-the 2nd and 6th values of the returned state cannot be relied upon.
-
-If the caller knows the PPSS of a nearby position, she can pass it
-in OLP-PPSS (with or without its corresponding OLD-POS) to try and
-avoid a more expansive scan.
-Point is at POS when this function returns."
- ;; Default values.
- (unless pos (setq pos (point)))
- ;;
- (let ((old-ppss (cdr syntax-ppss-last))
- (old-pos (car syntax-ppss-last))
- (ppss nil)
- (pt-min (point-min)))
- (if (and old-pos (> old-pos pos)) (setq old-pos nil))
- ;; Use the OLD-POS if usable and close. Don't update the `last' cache.
- (if (and old-pos (< (- pos old-pos)
- ;; The time to find PPSS using syntax-begin-function
- ;; is assumed to be about 2 * distance.
- (* 2 (/ (cdr (aref syntax-ppss-stats 5))
- (1+ (car (aref syntax-ppss-stats 5)))))))
- (progn
- (incf (car (aref syntax-ppss-stats 0)))
- (incf (cdr (aref syntax-ppss-stats 0)) (- pos old-pos))
- (parse-partial-sexp old-pos pos nil nil old-ppss))
-
- (cond
- ;; Use OLD-PPSS if possible and close enough.
- ((and (not old-pos) old-ppss
- ;; BEWARE! We rely on the undocumented 9th field.
- ;; The 9th field currently contains the list of positions
- ;; of open-parens of the enclosing parens. I.e. those positions
- ;; are outside of any string/comment and the first of those is
- ;; outside of any paren (i.e. corresponds to a nil ppss).
- ;; If this list is empty but we are in a string or comment,
- ;; then the 8th field contains a similar "toplevel" position.
- ;; If `pt-min' is too far from `pos', we could try to use
- ;; other positions in (nth 9 old-ppss), but that doesn't seem
- ;; to happen in practice and it would complicate this code
- ;; (and the after-change-function code even more). But maybe it
- ;; would be useful in "degenerate" cases such as when the whole
- ;; file is wrapped in a set of parenthesis.
- (setq pt-min (or (car (nth 9 old-ppss))
- (nth 8 old-ppss)
- (nth 2 old-ppss)))
- (<= pt-min pos) (< (- pos pt-min) syntax-ppss-max-span))
- (incf (car (aref syntax-ppss-stats 1)))
- (incf (cdr (aref syntax-ppss-stats 1)) (- pos pt-min))
- (setq ppss (parse-partial-sexp pt-min pos)))
- ;; The OLD-* data can't be used. Consult the cache.
- (t
- (let ((cache-pred nil)
- (cache syntax-ppss-cache)
- (pt-min (point-min))
- ;; I differentiate between PT-MIN and PT-BEST because I feel
- ;; like it might be important to ensure that the cache is only
- ;; filled with 100% sure data (whereas syntax-begin-function
- ;; might return incorrect data). Maybe that's just stupid.
- (pt-best (point-min))
- (ppss-best nil))
- ;; look for a usable cache entry.
- (while (and cache (< pos (caar cache)))
- (setq cache-pred cache)
- (setq cache (cdr cache)))
- (if cache (setq pt-min (caar cache) ppss (cdar cache)))
-
- ;; Setup the after-change function if necessary.
- (unless (or syntax-ppss-cache syntax-ppss-last)
- (add-hook 'after-change-functions
- 'syntax-ppss-after-change-function nil t))
-
- ;; Use the best of OLD-POS and CACHE.
- (if (or (not old-pos) (< old-pos pt-min))
- (setq pt-best pt-min ppss-best ppss)
- (incf (car (aref syntax-ppss-stats 4)))
- (incf (cdr (aref syntax-ppss-stats 4)) (- pos old-pos))
- (setq pt-best old-pos ppss-best old-ppss))
-
- ;; Use the `syntax-begin-function' if available.
- ;; We could try using that function earlier, but:
- ;; - The result might not be 100% reliable, so it's better to use
- ;; the cache if available.
- ;; - The function might be slow.
- ;; - If this function almost always finds a safe nearby spot,
- ;; the cache won't be populated, so consulting it is cheap.
- (unless (or syntax-begin-function
- (not (boundp 'font-lock-beginning-of-syntax-function))
- (not font-lock-beginning-of-syntax-function))
- (set (make-local-variable 'syntax-begin-function)
- font-lock-beginning-of-syntax-function))
- (when (and syntax-begin-function
- (progn (goto-char pos)
- (funcall syntax-begin-function)
- ;; Make sure it's better.
- (> (point) pt-best))
- ;; Simple sanity check.
- (not (memq (get-text-property (point) 'face)
- '(font-lock-string-face font-lock-comment-face
- font-lock-doc-face))))
- (incf (car (aref syntax-ppss-stats 5)))
- (incf (cdr (aref syntax-ppss-stats 5)) (- pos (point)))
- (setq pt-best (point) ppss-best nil))
-
- (cond
- ;; Quick case when we found a nearby pos.
- ((< (- pos pt-best) syntax-ppss-max-span)
- (incf (car (aref syntax-ppss-stats 2)))
- (incf (cdr (aref syntax-ppss-stats 2)) (- pos pt-best))
- (setq ppss (parse-partial-sexp pt-best pos nil nil ppss-best)))
- ;; Slow case: compute the state from some known position and
- ;; populate the cache so we won't need to do it again soon.
- (t
- (incf (car (aref syntax-ppss-stats 3)))
- (incf (cdr (aref syntax-ppss-stats 3)) (- pos pt-min))
-
- ;; If `pt-min' is too far, add a few intermediate entries.
- (while (> (- pos pt-min) (* 2 syntax-ppss-max-span))
- (setq ppss (parse-partial-sexp
- pt-min (setq pt-min (/ (+ pt-min pos) 2))
- nil nil ppss))
- (let ((pair (cons pt-min ppss)))
- (if cache-pred
- (push pair (cdr cache-pred))
- (push pair syntax-ppss-cache))))
-
- ;; Compute the actual return value.
- (setq ppss (parse-partial-sexp pt-min pos nil nil ppss))
-
- ;; Debugging check.
- ;; (let ((real-ppss (parse-partial-sexp (point-min) pos)))
- ;; (setcar (last ppss 4) 0)
- ;; (setcar (last real-ppss 4) 0)
- ;; (setcar (last ppss 8) nil)
- ;; (setcar (last real-ppss 8) nil)
- ;; (unless (equal ppss real-ppss)
- ;; (message "!!Syntax: %s != %s" ppss real-ppss)
- ;; (setq ppss real-ppss)))
-
- ;; Store it in the cache.
- (let ((pair (cons pos ppss)))
- (if cache-pred
- (if (> (- (caar cache-pred) pos) syntax-ppss-max-span)
- (push pair (cdr cache-pred))
- (setcar cache-pred pair))
- (if (or (null syntax-ppss-cache)
- (> (- (caar syntax-ppss-cache) pos)
- syntax-ppss-max-span))
- (push pair syntax-ppss-cache)
- (setcar syntax-ppss-cache pair)))))))))
-
- (setq syntax-ppss-last (cons pos ppss))
- ppss)))
-
-;; Debugging functions
-
-(defun syntax-ppss-debug ()
- (let ((pt nil)
- (min-diffs nil))
- (dolist (x (append syntax-ppss-cache (list (cons (point-min) nil))))
- (when pt (push (- pt (car x)) min-diffs))
- (setq pt (car x)))
- min-diffs))
-
-;; XEmacs compatibility functions
-
-;; (defun buffer-syntactic-context (&optional buffer)
-;; "Syntactic context at point in BUFFER.
-;; Either of `string', `comment' or `nil'.
-;; This is an XEmacs compatibility function."
-;; (with-current-buffer (or buffer (current-buffer))
-;; (syntax-ppss-context (syntax-ppss))))
-
-;; (defun buffer-syntactic-context-depth (&optional buffer)
-;; "Syntactic parenthesis depth at point in BUFFER.
-;; This is an XEmacs compatibility function."
-;; (with-current-buffer (or buffer (current-buffer))
-;; (syntax-ppss-depth (syntax-ppss))))
-
-(defun syntax-after (pos)
- "Return the syntax of the char after POS."
- (unless (or (< pos (point-min)) (>= pos (point-max)))
- (let ((st (if parse-sexp-lookup-properties
- (get-char-property pos 'syntax-table))))
- (if (consp st) st
- (aref (or st (syntax-table)) (char-after pos))))))
-
-(provide 'syntax)
-;;; syntax.el ends here
+;;; syntax.el --- helper functions to find syntactic context
+
+;; Copyright (C) 2000-2012 Free Software Foundation, Inc.
+
+;; Maintainer: FSF
+;; Keywords: internal
+
+;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; The main exported function is `syntax-ppss'. You might also need
+;; to call `syntax-ppss-flush-cache' or to add it to
+;; before-change-functions'(although this is automatically done by
+;; syntax-ppss when needed, but that might fail if syntax-ppss is
+;; called in a context where before-change-functions is temporarily
+;; let-bound to nil).
+
+;;; Todo:
+
+;; - do something about the case where the syntax-table is changed.
+;; This typically happens with tex-mode and its `$' operator.
+;; - new functions `syntax-state', ... to replace uses of parse-partial-state
+;; with something higher-level (similar to syntax-ppss-context).
+;; - interaction with mmm-mode.
+
+;;; Code:
+
+;; Note: PPSS stands for `parse-partial-sexp state'
+
+(eval-when-compile (require 'cl))
+
+(defvar font-lock-beginning-of-syntax-function)
+
+;;; Applying syntax-table properties where needed.
+
+(defvar syntax-propertize-function nil
+ ;; Rather than a -functions hook, this is a -function because it's easier
+ ;; to do a single scan than several scans: with multiple scans, one cannot
+ ;; assume that the text before point has been propertized, so syntax-ppss
+ ;; gives unreliable results (and stores them in its cache to boot, so we'd
+ ;; have to flush that cache between each function, and we couldn't use
+ ;; syntax-ppss-flush-cache since that would not only flush the cache but also
+ ;; reset syntax-propertize--done which should not be done in this case).
+ "Mode-specific function to apply the syntax-table properties.
+Called with two arguments: START and END.
+This function can call `syntax-ppss' on any position before END, but it
+should not call `syntax-ppss-flush-cache', which means that it should not
+call `syntax-ppss' on some position and later modify the buffer on some
+earlier position.")
+
+(defvar syntax-propertize-chunk-size 500)
+
+(defvar syntax-propertize-extend-region-functions
+ '(syntax-propertize-wholelines)
+ "Special hook run just before proceeding to propertize a region.
+This is used to allow major modes to help `syntax-propertize' find safe buffer
+positions as beginning and end of the propertized region. Its most common use
+is to solve the problem of /identification/ of multiline elements by providing
+a function that tries to find such elements and move the boundaries such that
+they do not fall in the middle of one.
+Each function is called with two arguments (START and END) and it should return
+either a cons (NEW-START . NEW-END) or nil if no adjustment should be made.
+These functions are run in turn repeatedly until they all return nil.
+Put first the functions more likely to cause a change and cheaper to compute.")
+;; Mark it as a special hook which doesn't use any global setting
+;; (i.e. doesn't obey the element t in the buffer-local value).
+(make-variable-buffer-local 'syntax-propertize-extend-region-functions)
+
+(defun syntax-propertize-wholelines (start end)
+ (goto-char start)
+ (cons (line-beginning-position)
+ (progn (goto-char end)
+ (if (bolp) (point) (line-beginning-position 2)))))
+
+(defun syntax-propertize-multiline (beg end)
+ "Let `syntax-propertize' pay attention to the syntax-multiline property."
+ (when (and (> beg (point-min))
+ (get-text-property (1- beg) 'syntax-multiline))
+ (setq beg (or (previous-single-property-change beg 'syntax-multiline)
+ (point-min))))
+ ;;
+ (when (get-text-property end 'font-lock-multiline)
+ (setq end (or (text-property-any end (point-max)
+ 'syntax-multiline nil)
+ (point-max))))
+ (cons beg end))
+
+(defvar syntax-propertize--done -1
+ "Position up to which syntax-table properties have been set.")
+(make-variable-buffer-local 'syntax-propertize--done)
+
+(defun syntax-propertize--shift-groups (re n)
+ (replace-regexp-in-string
+ "\\\\(\\?\\([0-9]+\\):"
+ (lambda (s)
+ (replace-match
+ (number-to-string (+ n (string-to-number (match-string 1 s))))
+ t t s 1))
+ re t t))
+
+(defmacro syntax-propertize-precompile-rules (&rest rules)
+ "Return a precompiled form of RULES to pass to `syntax-propertize-rules'.
+The arg RULES can be of the same form as in `syntax-propertize-rules'.
+The return value is an object that can be passed as a rule to
+`syntax-propertize-rules'.
+I.e. this is useful only when you want to share rules among several
+syntax-propertize-functions."
+ (declare (debug syntax-propertize-rules))
+ ;; Precompile? Yeah, right!
+ ;; Seriously, tho, this is a macro for 2 reasons:
+ ;; - we could indeed do some pre-compilation at some point in the future,
+ ;; e.g. fi/when we switch to a DFA-based implementation of
+ ;; syntax-propertize-rules.
+ ;; - this lets Edebug properly annotate the expressions inside RULES.
+ `',rules)
+
+(defmacro syntax-propertize-rules (&rest rules)
+ "Make a function that applies RULES for use in `syntax-propertize-function'.
+The function will scan the buffer, applying the rules where they match.
+The buffer is scanned a single time, like \"lex\" would, rather than once
+per rule.
+
+Each RULE can be a symbol, in which case that symbol's value should be,
+at macro-expansion time, a precompiled set of rules, as returned
+by `syntax-propertize-precompile-rules'.
+
+Otherwise, RULE should have the form (REGEXP HIGHLIGHT1 ... HIGHLIGHTn), where
+REGEXP is an expression (evaluated at time of macro-expansion) that returns
+a regexp, and where HIGHLIGHTs have the form (NUMBER SYNTAX) which means to
+apply the property SYNTAX to the chars matched by the subgroup NUMBER
+of the regular expression, if NUMBER did match.
+SYNTAX is an expression that returns a value to apply as `syntax-table'
+property. Some expressions are handled specially:
+- if SYNTAX is a string, then it is converted with `string-to-syntax';
+- if SYNTAX has the form (prog1 EXP . EXPS) then the value returned by EXP
+ will be applied to the buffer before running EXPS and if EXP is a string it
+ is also converted with `string-to-syntax'.
+The SYNTAX expression is responsible to save the `match-data' if needed
+for subsequent HIGHLIGHTs.
+Also SYNTAX is free to move point, in which case RULES may not be applied to
+some parts of the text or may be applied several times to other parts.
+
+Note: back-references in REGEXPs do not work."
+ (declare (debug (&rest &or symbolp ;FIXME: edebug this eval step.
+ (form &rest
+ (numberp
+ [&or stringp ;FIXME: Use &wrap
+ ("prog1" [&or stringp def-form] def-body)
+ def-form])))))
+ (let ((newrules nil))
+ (while rules
+ (if (symbolp (car rules))
+ (setq rules (append (symbol-value (pop rules)) rules))
+ (push (pop rules) newrules)))
+ (setq rules (nreverse newrules)))
+ (let* ((offset 0)
+ (branches '())
+ ;; We'd like to use a real DFA-based lexer, usually, but since Emacs
+ ;; doesn't have one yet, we fallback on building one large regexp
+ ;; and use groups to determine which branch of the regexp matched.
+ (re
+ (mapconcat
+ (lambda (rule)
+ (let* ((orig-re (eval (car rule)))
+ (re orig-re))
+ (when (and (assq 0 rule) (cdr rules))
+ ;; If there's more than 1 rule, and the rule want to apply
+ ;; highlight to match 0, create an extra group to be able to
+ ;; tell when *this* match 0 has succeeded.
+ (incf offset)
+ (setq re (concat "\\(" re "\\)")))
+ (setq re (syntax-propertize--shift-groups re offset))
+ (let ((code '())
+ (condition
+ (cond
+ ((assq 0 rule) (if (zerop offset) t
+ `(match-beginning ,offset)))
+ ((null (cddr rule))
+ `(match-beginning ,(+ offset (car (cadr rule)))))
+ (t
+ `(or ,@(mapcar
+ (lambda (case)
+ `(match-beginning ,(+ offset (car case))))
+ (cdr rule))))))
+ (nocode t)
+ (offset offset))
+ ;; If some of the subgroup rules include Elisp code, then we
+ ;; need to set the match-data so it's consistent with what the
+ ;; code expects. If not, then we can simply use shifted
+ ;; offset in our own code.
+ (unless (zerop offset)
+ (dolist (case (cdr rule))
+ (unless (stringp (cadr case))
+ (setq nocode nil)))
+ (unless nocode
+ (push `(let ((md (match-data 'ints)))
+ ;; Keep match 0 as is, but shift everything else.
+ (setcdr (cdr md) (nthcdr ,(* (1+ offset) 2) md))
+ (set-match-data md))
+ code)
+ (setq offset 0)))
+ ;; Now construct the code for each subgroup rules.
+ (dolist (case (cdr rule))
+ (assert (null (cddr case)))
+ (let* ((gn (+ offset (car case)))
+ (action (nth 1 case))
+ (thiscode
+ (cond
+ ((stringp action)
+ `((put-text-property
+ (match-beginning ,gn) (match-end ,gn)
+ 'syntax-table
+ ',(string-to-syntax action))))
+ ((eq (car-safe action) 'ignore)
+ (cdr action))
+ ((eq (car-safe action) 'prog1)
+ (if (stringp (nth 1 action))
+ `((put-text-property
+ (match-beginning ,gn) (match-end ,gn)
+ 'syntax-table
+ ',(string-to-syntax (nth 1 action)))
+ ,@(nthcdr 2 action))
+ `((let ((mb (match-beginning ,gn))
+ (me (match-end ,gn))
+ (syntax ,(nth 1 action)))
+ (if syntax
+ (put-text-property
+ mb me 'syntax-table syntax))
+ ,@(nthcdr 2 action)))))
+ (t
+ `((let ((mb (match-beginning ,gn))
+ (me (match-end ,gn))
+ (syntax ,action))
+ (if syntax
+ (put-text-property
+ mb me 'syntax-table syntax))))))))
+
+ (if (or (not (cddr rule)) (zerop gn))
+ (setq code (nconc (nreverse thiscode) code))
+ (push `(if (match-beginning ,gn)
+ ;; Try and generate clean code with no
+ ;; extraneous progn.
+ ,(if (null (cdr thiscode))
+ (car thiscode)
+ `(progn ,@thiscode)))
+ code))))
+ (push (cons condition (nreverse code))
+ branches))
+ (incf offset (regexp-opt-depth orig-re))
+ re))
+ rules
+ "\\|")))
+ `(lambda (start end)
+ (goto-char start)
+ (while (and (< (point) end)
+ (re-search-forward ,re end t))
+ (cond ,@(nreverse branches))))))
+
+(defun syntax-propertize-via-font-lock (keywords)
+ "Propertize for syntax in START..END using font-lock syntax.
+KEYWORDS obeys the format used in `font-lock-syntactic-keywords'.
+The return value is a function suitable for `syntax-propertize-function'."
+ (lexical-let ((keywords keywords))
+ (lambda (start end)
+ (with-no-warnings
+ (let ((font-lock-syntactic-keywords keywords))
+ (font-lock-fontify-syntactic-keywords-region start end)
+ ;; In case it was eval'd/compiled.
+ (setq keywords font-lock-syntactic-keywords))))))
+
+(defun syntax-propertize (pos)
+ "Ensure that syntax-table properties are set until POS."
+ (when (and syntax-propertize-function
+ (< syntax-propertize--done pos))
+ ;; (message "Needs to syntax-propertize from %s to %s"
+ ;; syntax-propertize--done pos)
+ (set (make-local-variable 'parse-sexp-lookup-properties) t)
+ (save-excursion
+ (with-silent-modifications
+ (let* ((start (max syntax-propertize--done (point-min)))
+ (end (max pos
+ (min (point-max)
+ (+ start syntax-propertize-chunk-size))))
+ (funs syntax-propertize-extend-region-functions))
+ (while funs
+ (let ((new (funcall (pop funs) start end)))
+ (if (or (null new)
+ (and (>= (car new) start) (<= (cdr new) end)))
+ nil
+ (setq start (car new))
+ (setq end (cdr new))
+ ;; If there's been a change, we should go through the
+ ;; list again since this new position may
+ ;; warrant a different answer from one of the funs we've
+ ;; already seen.
+ (unless (eq funs
+ (cdr syntax-propertize-extend-region-functions))
+ (setq funs syntax-propertize-extend-region-functions)))))
+ ;; Move the limit before calling the function, so the function
+ ;; can use syntax-ppss.
+ (setq syntax-propertize--done end)
+ ;; (message "syntax-propertizing from %s to %s" start end)
+ (remove-text-properties start end
+ '(syntax-table nil syntax-multiline nil))
+ (funcall syntax-propertize-function start end))))))
+
+;;; Incrementally compute and memoize parser state.
+
+(defsubst syntax-ppss-depth (ppss)
+ (nth 0 ppss))
+
+(defun syntax-ppss-toplevel-pos (ppss)
+ "Get the latest syntactically outermost position found in a syntactic scan.
+PPSS is a scan state, as returned by `parse-partial-sexp' or `syntax-ppss'.
+An \"outermost position\" means one that it is outside of any syntactic entity:
+outside of any parentheses, comments, or strings encountered in the scan.
+If no such position is recorded in PPSS (because the end of the scan was
+itself at the outermost level), return nil."
+ ;; BEWARE! We rely on the undocumented 9th field. The 9th field currently
+ ;; contains the list of positions of the enclosing open-parens.
+ ;; I.e. those positions are outside of any string/comment and the first of
+ ;; those is outside of any paren (i.e. corresponds to a nil ppss).
+ ;; If this list is empty but we are in a string or comment, then the 8th
+ ;; field contains a similar "toplevel" position.
+ (or (car (nth 9 ppss))
+ (nth 8 ppss)))
+
+(defsubst syntax-ppss-context (ppss)
+ (cond
+ ((nth 3 ppss) 'string)
+ ((nth 4 ppss) 'comment)
+ (t nil)))
+
+(defvar syntax-ppss-max-span 20000
+ "Threshold below which cache info is deemed unnecessary.
+We try to make sure that cache entries are at least this far apart
+from each other, to avoid keeping too much useless info.")
+
+(defvar syntax-begin-function nil
+ "Function to move back outside of any comment/string/paren.
+This function should move the cursor back to some syntactically safe
+point (where the PPSS is equivalent to nil).")
+
+(defvar syntax-ppss-cache nil
+ "List of (POS . PPSS) pairs, in decreasing POS order.")
+(make-variable-buffer-local 'syntax-ppss-cache)
+(defvar syntax-ppss-last nil
+ "Cache of (LAST-POS . LAST-PPSS).")
+(make-variable-buffer-local 'syntax-ppss-last)
+
+(defalias 'syntax-ppss-after-change-function 'syntax-ppss-flush-cache)
+(defun syntax-ppss-flush-cache (beg &rest ignored)
+ "Flush the cache of `syntax-ppss' starting at position BEG."
+ ;; Set syntax-propertize to refontify anything past beg.
+ (setq syntax-propertize--done (min beg syntax-propertize--done))
+ ;; Flush invalid cache entries.
+ (while (and syntax-ppss-cache (> (caar syntax-ppss-cache) beg))
+ (setq syntax-ppss-cache (cdr syntax-ppss-cache)))
+ ;; Throw away `last' value if made invalid.
+ (when (< beg (or (car syntax-ppss-last) 0))
+ ;; If syntax-begin-function jumped to BEG, then the old state at BEG can
+ ;; depend on the text after BEG (which is presumably changed). So if
+ ;; BEG=(car (nth 10 syntax-ppss-last)) don't reuse that data because the
+ ;; assumed nil state at BEG may not be valid any more.
+ (if (<= beg (or (syntax-ppss-toplevel-pos (cdr syntax-ppss-last))
+ (nth 3 syntax-ppss-last)
+ 0))
+ (setq syntax-ppss-last nil)
+ (setcar syntax-ppss-last nil)))
+ ;; Unregister if there's no cache left. Sadly this doesn't work
+ ;; because `before-change-functions' is temporarily bound to nil here.
+ ;; (unless syntax-ppss-cache
+ ;; (remove-hook 'before-change-functions 'syntax-ppss-flush-cache t))
+ )
+
+(defvar syntax-ppss-stats
+ [(0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (0 . 0.0) (1 . 2500.0)])
+(defun syntax-ppss-stats ()
+ (mapcar (lambda (x)
+ (condition-case nil
+ (cons (car x) (truncate (/ (cdr x) (car x))))
+ (error nil)))
+ syntax-ppss-stats))
+
+(defun syntax-ppss (&optional pos)
+ "Parse-Partial-Sexp State at POS, defaulting to point.
+The returned value is the same as that of `parse-partial-sexp'
+run from point-min to POS except that values at positions 2 and 6
+in the returned list (counting from 0) cannot be relied upon.
+Point is at POS when this function returns."
+ ;; Default values.
+ (unless pos (setq pos (point)))
+ (syntax-propertize pos)
+ ;;
+ (let ((old-ppss (cdr syntax-ppss-last))
+ (old-pos (car syntax-ppss-last))
+ (ppss nil)
+ (pt-min (point-min)))
+ (if (and old-pos (> old-pos pos)) (setq old-pos nil))
+ ;; Use the OLD-POS if usable and close. Don't update the `last' cache.
+ (condition-case nil
+ (if (and old-pos (< (- pos old-pos)
+ ;; The time to use syntax-begin-function and
+ ;; find PPSS is assumed to be about 2 * distance.
+ (* 2 (/ (cdr (aref syntax-ppss-stats 5))
+ (1+ (car (aref syntax-ppss-stats 5)))))))
+ (progn
+ (incf (car (aref syntax-ppss-stats 0)))
+ (incf (cdr (aref syntax-ppss-stats 0)) (- pos old-pos))
+ (parse-partial-sexp old-pos pos nil nil old-ppss))
+
+ (cond
+ ;; Use OLD-PPSS if possible and close enough.
+ ((and (not old-pos) old-ppss
+ ;; If `pt-min' is too far from `pos', we could try to use
+ ;; other positions in (nth 9 old-ppss), but that doesn't
+ ;; seem to happen in practice and it would complicate this
+ ;; code (and the before-change-function code even more).
+ ;; But maybe it would be useful in "degenerate" cases such
+ ;; as when the whole file is wrapped in a set
+ ;; of parentheses.
+ (setq pt-min (or (syntax-ppss-toplevel-pos old-ppss)
+ (nth 2 old-ppss)))
+ (<= pt-min pos) (< (- pos pt-min) syntax-ppss-max-span))
+ (incf (car (aref syntax-ppss-stats 1)))
+ (incf (cdr (aref syntax-ppss-stats 1)) (- pos pt-min))
+ (setq ppss (parse-partial-sexp pt-min pos)))
+ ;; The OLD-* data can't be used. Consult the cache.
+ (t
+ (let ((cache-pred nil)
+ (cache syntax-ppss-cache)
+ (pt-min (point-min))
+ ;; I differentiate between PT-MIN and PT-BEST because
+ ;; I feel like it might be important to ensure that the
+ ;; cache is only filled with 100% sure data (whereas
+ ;; syntax-begin-function might return incorrect data).
+ ;; Maybe that's just stupid.
+ (pt-best (point-min))
+ (ppss-best nil))
+ ;; look for a usable cache entry.
+ (while (and cache (< pos (caar cache)))
+ (setq cache-pred cache)
+ (setq cache (cdr cache)))
+ (if cache (setq pt-min (caar cache) ppss (cdar cache)))
+
+ ;; Setup the before-change function if necessary.
+ (unless (or syntax-ppss-cache syntax-ppss-last)
+ (add-hook 'before-change-functions
+ 'syntax-ppss-flush-cache t t))
+
+ ;; Use the best of OLD-POS and CACHE.
+ (if (or (not old-pos) (< old-pos pt-min))
+ (setq pt-best pt-min ppss-best ppss)
+ (incf (car (aref syntax-ppss-stats 4)))
+ (incf (cdr (aref syntax-ppss-stats 4)) (- pos old-pos))
+ (setq pt-best old-pos ppss-best old-ppss))
+
+ ;; Use the `syntax-begin-function' if available.
+ ;; We could try using that function earlier, but:
+ ;; - The result might not be 100% reliable, so it's better to use
+ ;; the cache if available.
+ ;; - The function might be slow.
+ ;; - If this function almost always finds a safe nearby spot,
+ ;; the cache won't be populated, so consulting it is cheap.
+ (when (and (not syntax-begin-function)
+ (boundp 'font-lock-beginning-of-syntax-function)
+ font-lock-beginning-of-syntax-function)
+ (set (make-local-variable 'syntax-begin-function)
+ font-lock-beginning-of-syntax-function))
+ (when (and syntax-begin-function
+ (progn (goto-char pos)
+ (funcall syntax-begin-function)
+ ;; Make sure it's better.
+ (> (point) pt-best))
+ ;; Simple sanity checks.
+ (< (point) pos) ; backward-paragraph can fail here.
+ (not (memq (get-text-property (point) 'face)
+ '(font-lock-string-face font-lock-doc-face
+ font-lock-comment-face))))
+ (incf (car (aref syntax-ppss-stats 5)))
+ (incf (cdr (aref syntax-ppss-stats 5)) (- pos (point)))
+ (setq pt-best (point) ppss-best nil))
+
+ (cond
+ ;; Quick case when we found a nearby pos.
+ ((< (- pos pt-best) syntax-ppss-max-span)
+ (incf (car (aref syntax-ppss-stats 2)))
+ (incf (cdr (aref syntax-ppss-stats 2)) (- pos pt-best))
+ (setq ppss (parse-partial-sexp pt-best pos nil nil ppss-best)))
+ ;; Slow case: compute the state from some known position and
+ ;; populate the cache so we won't need to do it again soon.
+ (t
+ (incf (car (aref syntax-ppss-stats 3)))
+ (incf (cdr (aref syntax-ppss-stats 3)) (- pos pt-min))
+
+ ;; If `pt-min' is too far, add a few intermediate entries.
+ (while (> (- pos pt-min) (* 2 syntax-ppss-max-span))
+ (setq ppss (parse-partial-sexp
+ pt-min (setq pt-min (/ (+ pt-min pos) 2))
+ nil nil ppss))
+ (let ((pair (cons pt-min ppss)))
+ (if cache-pred
+ (push pair (cdr cache-pred))
+ (push pair syntax-ppss-cache))))
+
+ ;; Compute the actual return value.
+ (setq ppss (parse-partial-sexp pt-min pos nil nil ppss))
+
+ ;; Debugging check.
+ ;; (let ((real-ppss (parse-partial-sexp (point-min) pos)))
+ ;; (setcar (last ppss 4) 0)
+ ;; (setcar (last real-ppss 4) 0)
+ ;; (setcar (last ppss 8) nil)
+ ;; (setcar (last real-ppss 8) nil)
+ ;; (unless (equal ppss real-ppss)
+ ;; (message "!!Syntax: %s != %s" ppss real-ppss)
+ ;; (setq ppss real-ppss)))
+
+ ;; Store it in the cache.
+ (let ((pair (cons pos ppss)))
+ (if cache-pred
+ (if (> (- (caar cache-pred) pos) syntax-ppss-max-span)
+ (push pair (cdr cache-pred))
+ (setcar cache-pred pair))
+ (if (or (null syntax-ppss-cache)
+ (> (- (caar syntax-ppss-cache) pos)
+ syntax-ppss-max-span))
+ (push pair syntax-ppss-cache)
+ (setcar syntax-ppss-cache pair)))))))))
+
+ (setq syntax-ppss-last (cons pos ppss))
+ ppss)
+ (args-out-of-range
+ ;; If the buffer is more narrowed than when we built the cache,
+ ;; we may end up calling parse-partial-sexp with a position before
+ ;; point-min. In that case, just parse from point-min assuming
+ ;; a nil state.
+ (parse-partial-sexp (point-min) pos)))))
+
+;; Debugging functions
+
+(defun syntax-ppss-debug ()
+ (let ((pt nil)
+ (min-diffs nil))
+ (dolist (x (append syntax-ppss-cache (list (cons (point-min) nil))))
+ (when pt (push (- pt (car x)) min-diffs))
+ (setq pt (car x)))
+ min-diffs))
+
+;; XEmacs compatibility functions
+
+;; (defun buffer-syntactic-context (&optional buffer)
+;; "Syntactic context at point in BUFFER.
+;; Either of `string', `comment' or `nil'.
+;; This is an XEmacs compatibility function."
+;; (with-current-buffer (or buffer (current-buffer))
+;; (syntax-ppss-context (syntax-ppss))))
+
+;; (defun buffer-syntactic-context-depth (&optional buffer)
+;; "Syntactic parenthesis depth at point in BUFFER.
+;; This is an XEmacs compatibility function."
+;; (with-current-buffer (or buffer (current-buffer))
+;; (syntax-ppss-depth (syntax-ppss))))
+
+(provide 'syntax)
+
+;;; syntax.el ends here
HCoop / bpt / emacs.git / blobdiff