X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/7be313ea3b46a5877b0f2b2ee6639f1c3d660fef..fa84f42ab93126b5552ec2058740dd5b410aa885:/lisp/tabify.el

diff --git a/lisp/tabify.el b/lisp/tabify.el
index 62d50aa033..971e1715ee 100644
--- a/lisp/tabify.el
+++ b/lisp/tabify.el
@@ -17,8 +17,9 @@
 ;; GNU General Public License for more details.
 
 ;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING.  If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
 
 ;;; Commentary:
 
@@ -39,13 +40,20 @@ The variable `tab-width' controls the spacing of tab stops."
       (narrow-to-region (point-min) end)
       (goto-char start)
       (while (search-forward "\t" nil t)	; faster than re-search
+	(forward-char -1)
 	(let ((tab-beg (point))
-	      (column (current-column))
-	      (indent-tabs-mode nil))
-	  (skip-chars-backward "\t" start)
+	      (indent-tabs-mode nil)
+	      column)
+	  (skip-chars-forward "\t")
+	  (setq column (current-column))
 	  (delete-region tab-beg (point))
 	  (indent-to column))))))
 
+(defvar tabify-regexp "[ \t][ \t]+"
+  "Regexp matching whitespace that tabify should consider.
+Usually this will be \"[ \\t][ \\t]+\" to match two or more spaces or tabs.
+\"^[ \\t]+\" is also useful, for tabifying only initial whitespace.")
+
 ;;;###autoload
 (defun tabify (start end)
   "Convert multiple spaces in region to tabs when possible.
@@ -63,7 +71,7 @@ The variable `tab-width' controls the spacing of tab stops."
       (beginning-of-line)
       (narrow-to-region (point) end)
       (goto-char start)
-      (while (re-search-forward "[ \t][ \t][ \t]*" nil t)
+      (while (re-search-forward tabify-regexp nil t)
 	(let ((column (current-column))
 	      (indent-tabs-mode t))
 	  (delete-region (match-beginning 0) (point))