-;;; syntax.el --- Helper functions to find syntactic context
+;;; syntax.el --- helper functions to find syntactic context
-;; Copyright (C) 2000 Free Software Foundation, Inc.
+;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
+;; 2005, 2006, 2007, 2008, 2009 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
+;; 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.
+;; 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
;; 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.
+;; 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-after-change-function' or to add it to
-;; after-change-functions'(although this is automatically done by
+;; 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 after-change-functions is temporarily
+;; called in a context where before-change-functions is temporarily
;; let-bound to nil).
;;; Todo:
;; - 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:
(eval-when-compile (require 'cl))
+(defvar font-lock-beginning-of-syntax-function)
+
(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 `partial-parse-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)
"Cache of (LAST-POS . LAST-PPSS).")
(make-variable-buffer-local 'syntax-ppss-last)
-(defun syntax-ppss-after-change-function (beg &rest ignored)
+(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."
;; 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))
+ ;; 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 `after-change-functions' is temporarily bound to nil here.
+ ;; because `before-change-functions' is temporarily bound to nil here.
;; (unless syntax-ppss-cache
- ;; (remove-hook 'after-change-functions
- ;; 'syntax-ppss-after-change-function t))
+ ;; (remove-hook 'before-change-functions 'syntax-ppss-flush-cache t))
)
(defvar syntax-ppss-stats
(error nil)))
syntax-ppss-stats))
-;;;###autoload
(defun syntax-ppss (&optional pos)
- "Parse-Partial-Sexp State at POS.
+ "Parse-Partial-Sexp State at POS, defaulting to point.
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))
+ (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
- ;; 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.
+ ;; 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
- (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)))
+ (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 check.
+ (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
;; (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)
+
+;; arch-tag: 302f1eeb-e77c-4680-a8c5-c543e01161a5
;;; syntax.el ends here