blink-matching-open does not work for text property parens

[Martin Stjernholm]

If a mode implements parens selectively on some characters using the
`syntax-table' text property (with parse-sexp-lookup-properties set to
non-nil) then the standard paren blinking function
`blink-matching-open' won't work correctly. The reason is that it uses
`char-syntax' and `matching-paren' on the character itself, without
regard to the properties it might have in the buffer. This patch fixes
that:


Index: lisp/simple.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/simple.el,v
retrieving revision 1.617
diff -C3 -r1.617 simple.el
*** lisp/simple.el      17 Aug 2003 00:15:53 -0000      1.617
--- lisp/simple.el      21 Aug 2003 20:43:08 -0000
***************
*** 3500,3506 ****
                           (point)))))
         (let* ((oldpos (point))
              (blinkpos)
!             (mismatch))
         (save-excursion
           (save-restriction
             (if blink-matching-paren-distance
--- 3500,3507 ----
                           (point)))))
         (let* ((oldpos (point))
              (blinkpos)
!             (mismatch)
!             matching-paren)
         (save-excursion
           (save-restriction
             (if blink-matching-paren-distance
***************
*** 3514,3525 ****
                   (setq blinkpos (scan-sexps oldpos -1)))
               (error nil)))
           (and blinkpos
!               (/= (char-syntax (char-after blinkpos))
!                   ?\$)
!               (setq mismatch
!                     (or (null (matching-paren (char-after blinkpos)))
                          (/= (char-after (1- oldpos))
!                             (matching-paren (char-after blinkpos))))))
           (if mismatch (setq blinkpos nil))
           (if blinkpos
               ;; Don't log messages about paren matching.
--- 3515,3534 ----
                   (setq blinkpos (scan-sexps oldpos -1)))
               (error nil)))
           (and blinkpos
!               (save-excursion
!                 (goto-char blinkpos)
!                 (not (looking-at "\\s$")))
!               (setq matching-paren
!                     (or (and parse-sexp-lookup-properties
!                              (let ((prop (get-text-property blinkpos 
'syntax-table)))
!                                (and (consp prop)
!                                     (eq (car prop) 4)
!                                     (cdr prop))))
!                         (matching-paren (char-after blinkpos)))
!                     mismatch
!                     (or (null matching-paren)
                          (/= (char-after (1- oldpos))
!                             matching-paren))))
           (if mismatch (setq blinkpos nil))
           (if blinkpos
               ;; Don't log messages about paren matching.



2003-08-21  Martin Stjernholm  <mast@lysator.liu.se>

        * simple.el (blink-matching-open): Work correctly on chars that
        are designated as parens through the syntax-table text property.