X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/e516799970be4553edae8ca46d5f64852befec77..03da5d089a8ed035cec443a27259e7d21487a22e:/lisp/tabify.el

diff --git a/lisp/tabify.el b/lisp/tabify.el
index eabaab10a4..8480983988 100644
--- a/lisp/tabify.el
+++ b/lisp/tabify.el
@@ -1,9 +1,9 @@
 ;;; tabify.el --- tab conversion commands for Emacs
 
-;; Maintainer: FSF
-;; Last-Modified: 09 May 1991
+;; Copyright (C) 1985, 1994, 2002, 2003, 2004,
+;;   2005 Free Software Foundation, Inc.
 
-;; Copyright (C) 1985 Free Software Foundation, Inc.
+;; Maintainer: FSF
 
 ;; This file is part of GNU Emacs.
 
@@ -18,43 +18,67 @@
 ;; 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., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+
+;;; Commentary:
+
+;; Commands to optimize spaces to tabs or expand tabs to spaces in a region
+;; (`tabify' and `untabify').  The variable tab-width does the obvious.
 
 ;;; Code:
 
 ;;;###autoload
 (defun untabify (start end)
   "Convert all tabs in region to multiple spaces, preserving columns.
-The variable tab-width controls the action."
+Called non-interactively, the region is specified by arguments
+START and END, rather than by the position of point and mark.
+The variable `tab-width' controls the spacing of tab stops."
   (interactive "r")
   (save-excursion
     (save-restriction
-      (narrow-to-region start end)
+      (narrow-to-region (point-min) end)
       (goto-char start)
       (while (search-forward "\t" nil t)	; faster than re-search
-	(let ((start (point))
-	      (column (current-column))
-	      (indent-tabs-mode nil))
-	  (skip-chars-backward "\t")
-	  (delete-region start (point))
+	(forward-char -1)
+	(let ((tab-beg (point))
+	      (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.
 A group of spaces is partially replaced by tabs
 when this can be done without changing the column they end at.
-The variable tab-width controls the action."
+Called non-interactively, the region is specified by arguments
+START and END, rather than by the position of point and mark.
+The variable `tab-width' controls the spacing of tab stops."
   (interactive "r")
   (save-excursion
     (save-restriction
-      (narrow-to-region start end)
+      ;; Include the beginning of the line in the narrowing
+      ;; since otherwise it will throw off current-column.
+      (goto-char start)
+      (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))
 	  (indent-to column))))))
 
+(provide 'tabify)
+
+;;; arch-tag: c83893b1-e0cc-4e57-8a09-73fd03466416
 ;;; tabify.el ends here