New function `string-mark-left-to-right' for handling LRMs.

* lisp/subr.el (string-mark-left-to-right): New function.

* lisp/buff-menu.el (Buffer-menu-buffer+size): Remove LRM argument.
Use string-mark-left-to-right.
(list-buffers-noselect): Caller changed.

* lisp/emacs-lisp/tabulated-list.el (tabulated-list-print-entry): Use
string-mark-left-to-right.
(tabulated-list-print): Recenter after moving point.

5 files changed, 39 insertions, 14 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 6a1bb6c1c5e..6f8c125f7f9 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1038,6 +1038,12 @@ 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.
+
 ** pre/post-command-hook are not reset to nil upon error.
 Instead, the offending function is removed.
 
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 780ea61a7ac..ad300b10f47 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,15 @@
+2011-08-10  Chong Yidong  <cyd@stupidchicken.com>
+
+        * subr.el (string-mark-left-to-right): New function.
+
+        * buff-menu.el (Buffer-menu-buffer+size): Remove LRM argument.
+        Use string-mark-left-to-right.
+        (list-buffers-noselect): Caller changed.
+
+        * emacs-lisp/tabulated-list.el (tabulated-list-print-entry): Use
+        string-mark-left-to-right.
+        (tabulated-list-print): Recenter after moving point.
+
 2011-08-10  Juri Linkov  <juri@jurta.org>
 
         * progmodes/grep.el (rgrep): Don't bind `process-connection-type'.
diff --git a/lisp/buff-menu.el b/lisp/buff-menu.el
index f0a44747378..a5b45921d28 100644
--- a/lisp/buff-menu.el
+++ b/lisp/buff-menu.el
@@ -666,7 +666,7 @@ For more information, see the function `buffer-menu'."
   ":" ;; (if (char-displayable-p ?…) "…" ":")
   )
 
-(defun Buffer-menu-buffer+size (name size &optional name-props size-props lrm)
+(defun Buffer-menu-buffer+size (name size &optional name-props size-props)
   (if (> (+ (string-width name) (string-width size) 2)
          Buffer-menu-buffer+size-width)
       (setq name
@@ -681,17 +681,9 @@ For more information, see the function `buffer-menu'."
                           (string-width tail)
                           2))
                       Buffer-menu-short-ellipsis
-                      tail
-                      ;; Append an invisible LRM character to the
-                      ;; buffer's name to avoid ugly display with the
-                      ;; buffer size to the left of the name, when the
-                      ;; name begins with R2L character.
-                      (if lrm (propertize (string ?\x200e) 'invisible t) ""))))
+                      (string-mark-left-to-right tail))))
     ;; Don't put properties on (buffer-name).
-    (setq name (concat (copy-sequence name)
-                       (if lrm
-                           (propertize (string ?\x200e) 'invisible t)
-                         ""))))
+    (setq name (string-mark-left-to-right name)))
   (add-text-properties 0 (length name) name-props name)
   (add-text-properties 0 (length size) size-props size)
   (let ((name+space-width (- Buffer-menu-buffer+size-width
@@ -929,8 +921,7 @@ For more information, see the function `buffer-menu'."
                                                    (max (length size) 3)
                                                    2))
                                             name
-                                          "mouse-2: select this buffer"))
-                         nil t))
+                                          "mouse-2: select this buffer"))))
                 "  "
                 (if (> (string-width (nth 4 buffer)) Buffer-menu-mode-width)
                     (truncate-string-to-width (nth 4 buffer)
diff --git a/lisp/emacs-lisp/tabulated-list.el b/lisp/emacs-lisp/tabulated-list.el
index 2fdfa9525b1..9b485b58608 100644
--- a/lisp/emacs-lisp/tabulated-list.el
+++ b/lisp/emacs-lisp/tabulated-list.el
@@ -258,7 +258,8 @@ to the entry with the same ID element as the current line."
     ;; If REMEMBER-POS was specified, move to the "old" location.
     (if saved-pt
         (progn (goto-char saved-pt)
-               (move-to-column saved-col))
+               (move-to-column saved-col)
+               (recenter))
       (goto-char (point-min)))))
 
 (defun tabulated-list-print-entry (id cols)
@@ -282,6 +283,7 @@ of column descriptors."
              (> (length label) width)
              (setq label (concat (substring label 0 (- width 3))
                                  "...")))
+        (setq label (string-mark-left-to-right label))
         (if (stringp desc)
             (insert (propertize label 'help-echo help-echo))
           (apply 'insert-text-button label (cdr desc)))
diff --git a/lisp/subr.el b/lisp/subr.el
index d57c507a548..a897da1d9ba 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3538,6 +3538,20 @@ If IGNORE-CASE is non-nil, the comparison is done without paying attention
 to case differences."
   (eq t (compare-strings str1 nil nil
                          str2 0 (length str1) ignore-case)))
+
+(defun string-mark-left-to-right (str)
+  "Return a string that can be safely embedded in left-to-right text.
+If STR ends in right-to-left (RTL) script, return a string
+consisting of STR followed by an invisible left-to-right
+mark (LRM) character.  Otherwise, return STR."
+  (unless (stringp str)
+    (signal 'wrong-type-argument (list 'stringp str)))
+  (if (and (> (length str) 0)
+           (eq (get-char-code-property (aref str (1- (length str)))
+                                       'bidi-class)
+               'R))
+      (concat str (propertize (string ?\x200e) 'invisible t))
+    str))
 
 ;;;; invisibility specs