(untabify): Handle consecutive tabs all at once.

(tabify-regexp): New var.
(tabify): Use it.

diff --git a/lisp/tabify.el b/lisp/tabify.el
index c5d76fcc2110496a54a112010648fdb577f845c7..971e1715eea5bea23017fe5fb13d8cb97150593e 100644 (file)
--- a/lisp/tabify.el
+++ b/lisp/tabify.el
@@ -40,13 +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.
@@ -64,7 +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))