lisp/tabify.el

   1 ;; Tab conversion commands for Emacs
   2 ;; Copyright (C) 1985 Free Software Foundation, Inc.
   3
   4 ;; This file is part of GNU Emacs.
   5
   6 ;; GNU Emacs is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 1, or (at your option)
   9 ;; any later version.
  10
  11 ;; GNU Emacs is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  18 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20
  21 ;;;###autoload
  22 (defun untabify (start end)
  23   "Convert all tabs in region to multiple spaces, preserving columns.
  24 The variable tab-width controls the action."
  25   (interactive "r")
  26   (save-excursion
  27     (save-restriction
  28       (narrow-to-region start end)
  29       (goto-char start)
  30       (while (search-forward "\t" nil t)        ; faster than re-search
  31         (let ((start (point))
  32               (column (current-column))
  33               (indent-tabs-mode nil))
  34           (skip-chars-backward "\t")
  35           (delete-region start (point))
  36           (indent-to column))))))
  37
  38 ;;;###autoload
  39 (defun tabify (start end)
  40   "Convert multiple spaces in region to tabs when possible.
  41 A group of spaces is partially replaced by tabs
  42 when this can be done without changing the column they end at.
  43 The variable tab-width controls the action."
  44   (interactive "r")
  45   (save-excursion
  46     (save-restriction
  47       (narrow-to-region start end)
  48       (goto-char start)
  49       (while (re-search-forward "[ \t][ \t][ \t]*" nil t)
  50         (let ((column (current-column))
  51               (indent-tabs-mode t))
  52           (delete-region (match-beginning 0) (point))
  53           (indent-to column))))))