(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)))
(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)))
(and (save-excursion (re-search-backward page-delimiter nil t))
(= (match-end 0) (point))
(goto-char (match-beginning 0)))
(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 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)
(let ((adjust 0)
(opoint (point)))
(save-excursion
(beginning-of-line)
(or (and (looking-at page-delimiter)
(eq (match-end 0) opoint))
(setq adjust 1)))
(forward-page (- arg adjust)))))
(set-match-data nil)
(forward-page)
(if (and (match-beginning 0)
(save-excursion
(goto-char (match-beginning 0)) (looking-at page-delimiter)))
(goto-char (match-beginning 0))) (narrow-to-region (point)
(progn
(forward-page -1)
(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)))))))
(provide 'page)