inv-18.el

;;; inv-18.el --- invisible feature implementation for Emacs 18

;; Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.

;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
;; Keywords: invisible, text-property, region, Emacs 18

;; This file is part of APEL (A Portable Emacs Library).

;; 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, 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Code:

(defmacro enable-invisible ()
  (`
   (progn
     (make-local-variable 'original-selective-display)
     (setq original-selective-display selective-display)
     (setq selective-display t)
     )))

(defmacro end-of-invisible ()
  (` (setq selective-display
	   (if (boundp 'original-selective-display)
	       original-selective-display))
     ))

(defun invisible-region (start end)
  (let ((buffer-read-only nil)		;Okay even if write protected.
	(modp (buffer-modified-p)))
    (if (save-excursion
	  (goto-char (1- end))
	  (eq (following-char) ?\n)
	  )
	(setq end (1- end))
      )
    (unwind-protect
        (subst-char-in-region start end ?\n ?\^M t)
      (set-buffer-modified-p modp)
      )))

(defun visible-region (start end)
  (let ((buffer-read-only nil)		;Okay even if write protected.
	(modp (buffer-modified-p)))
    (unwind-protect
        (subst-char-in-region start end ?\^M ?\n t)
      (set-buffer-modified-p modp)
      )))

(defun invisible-p (pos)
  (save-excursion
    (goto-char pos)
    (eq (following-char) ?\^M)
    ))

(defun next-visible-point (pos)
  (save-excursion
    (goto-char pos)
    (end-of-line)
    (if (eq (following-char) ?\n)
	(forward-char)
      )
    (point)
    ))


;;; @ end
;;;

(provide 'inv-18)

;;; inv-18.el ends here