;;;; unique.el -- remove duplicate successive lines
;;; Time-stamp: <2006-12-01 18:17:19 jcgs>

;;  This program 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 of the License, or (at your
;;  option) any later version.

;;  This program 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 this program; if not, write to the Free Software Foundation, Inc.,
;;  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

(defun unique-lines (from to)
  "Remove duplicate lines between FROM and TO."
  ;; inspired by Un*x's "uniq" command
  (interactive "r")
  (goto-char to)
  (while (> (point) from)
    (beginning-of-line 1)
    (let* ((last-line-start (point))
	   (line (buffer-substring last-line-start (point-at-eol)))
	   (some nil))
      (beginning-of-line 0)
      (while (and (> (point) from)
		  (string= (buffer-substring (point) (point-at-eol))
			   line))
	(setq some t)
	(beginning-of-line 0))
      (when some
	(kill-region (point) last-line-start)))))

(provide 'unique)

;;; end of unique.el