;;; syntax.el --- helper functions to find syntactic context
-;; Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
+;; 2005, 2006, 2007 Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: internal
;; 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.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
;; The main exported function is `syntax-ppss'. You might also need
;; to call `syntax-ppss-flush-cache' or to add it to
-;; after-change-functions'(although this is automatically done by
+;; 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:
(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)
(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.
The returned value is the same as `parse-partial-sexp' except that
(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)
+ ;; 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)))
(setq cache (cdr cache)))
(if cache (setq pt-min (caar cache) ppss (cdar cache)))
- ;; Setup the after-change function if necessary.
+ ;; Setup the before-change function if necessary.
(unless (or syntax-ppss-cache syntax-ppss-last)
- (add-hook 'after-change-functions
- 'syntax-ppss-flush-cache nil t))
+ (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))
;; (syntax-ppss-depth (syntax-ppss))))
(provide 'syntax)
+
+;; arch-tag: 302f1eeb-e77c-4680-a8c5-c543e01161a5
;;; syntax.el ends here
HCoop / bpt / emacs.git / blobdiff