Fix behavior of string-mark-left-to-right.

* lisp/subr.el (string-mark-left-to-right): Search the entire string
for RTL script, not just the terminating character.  Doc fix.

1 files changed, 9 insertions, 5 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 6f8c125f7f..1a788e7f6f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1038,11 +1038,15 @@ of function value which looks like (closure ENV ARGS &rest BODY).
 *** New function `special-variable-p' to check whether a variable is
 declared as dynamically bound.
 
-** New function `string-mark-left-to-right' appends a Unicode LRM
-(left-to-right mark) character to a string if it terminates in
-right-to-left script.  This is useful when the buffer has overall
-left-to-right paragraph direction and you need to insert a string
-whose contents (and directionality) are not known in advance.
+** New function `string-mark-left-to-right'.
+Given a string containing right-to-left (RTL) script, this function
+returns another string with a terminating LRM (left-to-right mark)
+character.  If this string is inserted into a buffer, Emacs treats the
+LRM as the end of an RTL segment and displays following text as LTR.
+
+This is useful when the buffer has overall left-to-right (LTR)
+paragraph direction and you need to insert a string whose contents
+(and hence directionality) are not known in advance.
 
 ** pre/post-command-hook are not reset to nil upon error.
 Instead, the offending function is removed.