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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-09 09:10:16 +00:00
emacs/lisp/textmodes/page.el
Richard M. Stallman 07f4ea75c3 entered into RCS
1992-09-04 21:51:42 +00:00

136 lines
4.3 KiB
EmacsLisp

;;; page.el --- page motion commands for emacs.
;; Copyright (C) 1985 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.
;;; Code:
(defun forward-page (&optional count)
"Move forward to page boundary. With arg, repeat, or go back if negative.
A page boundary is any line whose beginning matches the regexp
`page-delimiter'."
(interactive "p")
(or count (setq count 1))
(while (and (> count 0) (not (eobp)))
;; In case the page-delimiter matches the null string,
;; don't find a match without moving.
(if (bolp) (forward-char 1))
(if (re-search-forward page-delimiter nil t)
nil
(goto-char (point-max)))
(setq count (1- count)))
(while (and (< count 0) (not (bobp)))
(forward-char -1)
(if (re-search-backward page-delimiter nil t)
(goto-char (match-end 0))
(goto-char (point-min)))
(setq count (1+ count))))
(defun backward-page (&optional count)
"Move backward to page boundary. With arg, repeat, or go fwd if negative.
A page boundary is any line whose beginning matches the regexp
`page-delimiter'."
(interactive "p")
(or count (setq count 1))
(forward-page (- count)))
(defun mark-page (&optional arg)
"Put mark at end of page, point at beginning.
A numeric arg specifies to move forward or backward by that many pages,
thus marking a page other than the one point was originally in."
(interactive "P")
(setq arg (if arg (prefix-numeric-value arg) 0))
(if (> arg 0)
(forward-page arg)
(if (< arg 0)
(forward-page (1- arg))))
(forward-page)
(push-mark nil t)
(forward-page -1))
(defun narrow-to-page (&optional arg)
"Make text outside current page invisible.
A numeric arg specifies to move forward or backward by that many pages,
thus showing a page other than the one point was originally in."
(interactive "P")
(setq arg (if arg (prefix-numeric-value arg) 0))
(save-excursion
(widen)
(if (> arg 0)
(forward-page arg)
(if (< arg 0)
(forward-page (1- arg))))
;; Find the end of the page.
(forward-page)
;; If we stopped due to end of buffer, stay there.
;; If we stopped after a page delimiter, put end of restriction
;; at the beginning of that line.
(if (save-excursion (beginning-of-line)
(looking-at page-delimiter))
(beginning-of-line))
(narrow-to-region (point)
(progn
;; Find the top of the page.
(forward-page -1)
;; If we found beginning of buffer, stay there.
;; If extra text follows page delimiter on same line,
;; include it.
;; Otherwise, show text starting with following line.
(if (and (eolp) (not (bobp)))
(forward-line 1))
(point)))))
(put 'narrow-to-page 'disabled t)
(defun count-lines-page ()
"Report number of lines on current page, and how many are before or after point."
(interactive)
(save-excursion
(let ((opoint (point)) beg end
total before after)
(forward-page)
(beginning-of-line)
(or (looking-at page-delimiter)
(end-of-line))
(setq end (point))
(backward-page)
(setq beg (point))
(setq total (count-lines beg end)
before (count-lines beg opoint)
after (count-lines opoint end))
(message "Page has %d lines (%d + %d)" total before after))))
(defun what-page ()
"Print page and line number of point."
(interactive)
(save-restriction
(widen)
(save-excursion
(beginning-of-line)
(let ((count 1)
(opoint (point)))
(goto-char 1)
(while (re-search-forward page-delimiter opoint t)
(setq count (1+ count)))
(message "Page %d, line %d"
count
(1+ (count-lines (point) opoint)))))))
;;; page.el ends here