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emacs/lisp/tabify.el
1995-04-13 17:04:57 +00:00

75 lines
2.6 KiB
EmacsLisp

;;; tabify.el --- tab conversion commands for Emacs
;; Copyright (C) 1985, 1994 Free Software Foundation, Inc.
;; Maintainer: FSF
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; 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.
;;; 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.
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 (point-min) end)
(goto-char start)
(while (search-forward "\t" nil t) ; faster than re-search
(let ((tab-beg (point))
(column (current-column))
(indent-tabs-mode nil))
(skip-chars-backward "\t" start)
(delete-region tab-beg (point))
(indent-to column))))))
;;;###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.
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
;; 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)
(let ((column (current-column))
(indent-tabs-mode t))
(delete-region (match-beginning 0) (point))
(indent-to column))))))
(provide 'tabify)
;;; tabify.el ends here