Fix current-bidi-paragraph-direction and its doc.

 src/xdisp.c (Fcurrent_bidi_paragraph_direction): For unibyte
 buffers, return left-to-right.
 doc/lispref/display.texi (Bidirectional Display): Document return value in
 buffers that are not bidi-reordered for display, and in unibyte
 buffers.

4 files changed, 14 insertions, 2 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 43add469ec0..4bf615328b1 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,9 @@
+2011-08-24  Eli Zaretskii  <eliz@gnu.org>
+
+        * display.texi (Bidirectional Display): Document return value in
+        buffers that are not bidi-reordered for display, and in unibyte
+        buffers.
+
 2011-08-23  Eli Zaretskii  <eliz@gnu.org>
 
         * nonascii.texi (Character Properties): Document the values for
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 8f7f4003411..0593eba8f05 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -6104,7 +6104,9 @@ omitted or @code{nil}, it defaults to the current buffer.  If the
 buffer-local value of the variable @code{bidi-paragraph-direction} is
 non-@code{nil}, the returned value will be identical to that value;
 otherwise, the returned value reflects the paragraph direction
-determined dynamically by Emacs.
+determined dynamically by Emacs.  For buffers whose value of
+@code{bidi-display-reordering} is @code{nil} as well as unibyte
+buffers, this function always returns @code{left-to-right}.
 @end defun
 
 @cindex layout on display, and bidirectional text
diff --git a/src/ChangeLog b/src/ChangeLog
index f52e8cad479..d4d6a4c4bbd 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,8 @@
 2011-08-24  Eli Zaretskii  <eliz@gnu.org>
 
+        * xdisp.c (Fcurrent_bidi_paragraph_direction): For unibyte
+        buffers, return left-to-right.
+
         * bidi.c (bidi_check_type): Use xassert.
         (bidi_cache_iterator_state): Update the disp_pos and disp_prop_p
         members.
diff --git a/src/xdisp.c b/src/xdisp.c
index 6a11628f858..8b3a71027b6 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -19014,7 +19014,8 @@ See also `bidi-paragraph-direction'.  */)
       buf = XBUFFER (buffer);
     }
 
-  if (NILP (BVAR (buf, bidi_display_reordering)))
+  if (NILP (BVAR (buf, bidi_display_reordering))
+      || NILP (BVAR (buf, enable_multibyte_characters)))
     return Qleft_to_right;
   else if (!NILP (BVAR (buf, bidi_paragraph_direction)))
     return BVAR (buf, bidi_paragraph_direction);