Re: [Emacs-diffs] /srv/bzr/emacs/trunk r105429: New function `string-mark-left-to-right' for handling LRMs.

[Chong Yidong <cyd@stupidchicken.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> We could also add a new special regexp construct, similar to \c but
> for Unicode properties.  The advantage being that it lets us use the
> Unicode tables without having to build a new category table that keeps
> another copy of it, and without having to use "(with-category-table
> special-category-table-for-bidi".

We can put it in the standard category table.  This works:

=== modified file 'lisp/international/characters.el'
*** lisp/international/characters.el	2011-07-06 22:43:48 +0000
--- lisp/international/characters.el	2011-08-14 02:21:19 +0000
***************
*** 114,119 ****
--- 114,123 ----
  Base characters (Unicode General Category L,N,P,S,Zs)")
  (define-category ?^ "Combining
  Combining diacritic or mark (Unicode General Category M)")
+ 
+ ;; RTL scripts
+ (define-category ?R "Right-to-left
+ Characters with R, AL, or RLO bidi type.")
  \f
  ;;; Setting syntax and category.
  
***************
*** 478,483 ****
--- 482,494 ----
  		  (modify-category-entry x category))
  	      chars)))))
  
+ ;; RTL scripts.
+ 
+ (map-char-table (lambda (key val)
+ 		  (if (memq val '(R AL RLO))
+ 		      (modify-category-entry key ?R)))
+ 		(unicode-property-table-internal 'bidi-class))
+ 
  ;; Latin
  
  (modify-category-entry '(#x80 . #x024F) ?l)

=== modified file 'lisp/subr.el'
*** lisp/subr.el	2011-08-12 15:43:30 +0000
--- lisp/subr.el	2011-08-13 15:42:16 +0000
***************
*** 3553,3568 ****
  If STR contains no RTL characters, return STR."
    (unless (stringp str)
      (signal 'wrong-type-argument (list 'stringp str)))
!   (let ((len (length str))
! 	(n 0)
! 	rtl-found)
!     (while (and (not rtl-found) (< n len))
!       (setq rtl-found (memq (get-char-code-property
! 			     (aref str n) 'bidi-class) '(R AL RLO))
! 	    n (1+ n)))
!     (if rtl-found
! 	(concat str (propertize (string ?\x200e) 'invisible t))
!       str)))
  \f
  ;;;; invisibility specs
  
--- 3553,3561 ----
  If STR contains no RTL characters, return STR."
    (unless (stringp str)
      (signal 'wrong-type-argument (list 'stringp str)))
!   (if (string-match "\\cR" str)
!       (concat str (propertize (string ?\x200e) 'invisible t))
!     str))
  \f
  ;;;; invisibility specs