Implement bidi-sensitive movement with arrow keys.

 src/bidi.c (bidi_paragraph_init): Don't leave alone garbage values
 of bidi_it->paragraph_dir.  Call bidi_initialize if needed.
 src/xdisp.c (Fcurrent_bidi_paragraph_direction): New function.
 (syms_of_xdisp): Defsubr it.
 src/cmds.c (Fforward_char, Fbackward_char): Doc fix.
 src/subr.el (right-arrow-command, left-arrow-command): New functions.
 src/bindings.el (global-map): Bind them to right and left arrow keys.
 etc/NEWS: Mention current-bidi-paragraph-direction

1 files changed, 25 insertions, 0 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 0cc05a78bc7..1c399f89b9c 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3804,5 +3804,30 @@ which is higher than \"1alpha\"."
 			  (prin1-to-string (make-hash-table)))))
   (provide 'hashtable-print-readable))
 
+;; Moving with arrows in bidi-sensitive direction.
+(defun right-arrow-command (&optional n)
+  "Move point N characters to the right (to the left if N is negative).
+On reaching beginning or end of buffer, stop and signal error.
+
+Depending on the bidirectional context, this may move either forward
+or backward in the buffer.  This is in contrast with \\[forward-char]
+and \\[backward-char], which see."
+  (interactive "^p")
+  (if (eq (current-bidi-paragraph-direction) 'left-to-right)
+      (forward-char n)
+    (backward-char n)))
+
+(defun left-arrow-command ( &optional n)
+  "Move point N characters to the left (to the right if N is negative).
+On reaching beginning or end of buffer, stop and signal error.
+
+Depending on the bidirectional context, this may move either backward
+or forward in the buffer.  This is in contrast with \\[backward-char]
+and \\[forward-char], which see."
+  (interactive "^p")
+  (if (eq (current-bidi-paragraph-direction) 'left-to-right)
+      (backward-char n)
+    (forward-char n)))
+
 ;; arch-tag: f7e0e6e5-70aa-4897-ae72-7a3511ec40bc
 ;;; subr.el ends here