Line data Source code
1 : ;;; page.el --- page motion commands for Emacs
2 :
3 : ;; Copyright (C) 1985, 2001-2017 Free Software Foundation, Inc.
4 :
5 : ;; Maintainer: emacs-devel@gnu.org
6 : ;; Keywords: wp convenience
7 : ;; Package: emacs
8 :
9 : ;; This file is part of GNU Emacs.
10 :
11 : ;; GNU Emacs is free software: you can redistribute it and/or modify
12 : ;; it under the terms of the GNU General Public License as published by
13 : ;; the Free Software Foundation, either version 3 of the License, or
14 : ;; (at your option) any later version.
15 :
16 : ;; GNU Emacs is distributed in the hope that it will be useful,
17 : ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 : ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 : ;; GNU General Public License for more details.
20 :
21 : ;; You should have received a copy of the GNU General Public License
22 : ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
23 :
24 : ;;; Commentary:
25 :
26 : ;; This code provides the page-oriented movement and selection commands
27 : ;; documented in the Emacs manual.
28 :
29 : ;;; Code:
30 :
31 : (defun forward-page (&optional count)
32 : "Move forward to page boundary. With arg, repeat, or go back if negative.
33 : A page boundary is any line whose beginning matches the regexp
34 : `page-delimiter'."
35 : (interactive "p")
36 0 : (or count (setq count 1))
37 0 : (while (and (> count 0) (not (eobp)))
38 : ;; In case the page-delimiter matches the null string,
39 : ;; don't find a match without moving.
40 0 : (if (bolp) (forward-char 1))
41 0 : (if (re-search-forward page-delimiter nil t)
42 : nil
43 0 : (goto-char (point-max)))
44 0 : (setq count (1- count)))
45 0 : (while (and (< count 0) (not (bobp)))
46 : ;; In case the page-delimiter matches the null string,
47 : ;; don't find a match without moving.
48 0 : (and (save-excursion (re-search-backward page-delimiter nil t))
49 0 : (= (match-end 0) (point))
50 0 : (goto-char (match-beginning 0)))
51 0 : (unless (bobp)
52 0 : (forward-char -1)
53 0 : (if (re-search-backward page-delimiter nil t)
54 : ;; We found one--move to the end of it.
55 0 : (goto-char (match-end 0))
56 : ;; We found nothing--go to beg of buffer.
57 0 : (goto-char (point-min))))
58 0 : (setq count (1+ count))))
59 :
60 : (defun backward-page (&optional count)
61 : "Move backward to page boundary. With arg, repeat, or go fwd if negative.
62 : A page boundary is any line whose beginning matches the regexp
63 : `page-delimiter'."
64 : (interactive "p")
65 0 : (or count (setq count 1))
66 0 : (forward-page (- count)))
67 :
68 : (defun mark-page (&optional arg)
69 : "Put mark at end of page, point at beginning.
70 : A numeric arg specifies to move forward or backward by that many pages,
71 : thus marking a page other than the one point was originally in."
72 : (interactive "P")
73 0 : (setq arg (if arg (prefix-numeric-value arg) 0))
74 0 : (if (> arg 0)
75 0 : (forward-page arg)
76 0 : (if (< arg 0)
77 0 : (forward-page (1- arg))))
78 0 : (forward-page)
79 0 : (push-mark nil t t)
80 0 : (forward-page -1))
81 :
82 : (defun narrow-to-page (&optional arg)
83 : "Make text outside current page invisible.
84 : A numeric arg specifies to move forward or backward by that many pages,
85 : thus showing a page other than the one point was originally in."
86 : (interactive "P")
87 0 : (setq arg (if arg (prefix-numeric-value arg) 0))
88 0 : (save-excursion
89 0 : (widen)
90 0 : (if (> arg 0)
91 0 : (forward-page arg)
92 0 : (if (< arg 0)
93 0 : (let ((adjust 0)
94 0 : (opoint (point)))
95 : ;; If we are not now at the beginning of a page,
96 : ;; move back one extra time, to get to the start of this page.
97 0 : (save-excursion
98 0 : (beginning-of-line)
99 0 : (or (and (looking-at page-delimiter)
100 0 : (eq (match-end 0) opoint))
101 0 : (setq adjust 1)))
102 0 : (forward-page (- arg adjust)))))
103 : ;; Find the end of the page.
104 0 : (set-match-data nil)
105 0 : (forward-page)
106 : ;; If we stopped due to end of buffer, stay there.
107 : ;; If we stopped after a page delimiter, put end of restriction
108 : ;; at the beginning of that line.
109 : ;; Before checking the match that was found,
110 : ;; verify that forward-page actually set the match data.
111 0 : (if (and (match-beginning 0)
112 0 : (save-excursion
113 0 : (goto-char (match-beginning 0)) ; was (beginning-of-line)
114 0 : (looking-at page-delimiter)))
115 0 : (goto-char (match-beginning 0))) ; was (beginning-of-line)
116 0 : (narrow-to-region (point)
117 0 : (progn
118 : ;; Find the top of the page.
119 0 : (forward-page -1)
120 : ;; If we found beginning of buffer, stay there.
121 : ;; If extra text follows page delimiter on same line,
122 : ;; include it.
123 : ;; Otherwise, show text starting with following line.
124 0 : (if (and (eolp) (not (bobp)))
125 0 : (forward-line 1))
126 0 : (point)))))
127 : (put 'narrow-to-page 'disabled t)
128 :
129 : (defun count-lines-page ()
130 : "Report number of lines on current page, and how many are before or after point."
131 : (interactive)
132 0 : (save-excursion
133 0 : (let ((opoint (point)) beg end
134 : total before after)
135 0 : (forward-page)
136 0 : (beginning-of-line)
137 0 : (or (looking-at page-delimiter)
138 0 : (end-of-line))
139 0 : (setq end (point))
140 0 : (backward-page)
141 0 : (setq beg (point))
142 0 : (setq total (count-lines beg end)
143 0 : before (count-lines beg opoint)
144 0 : after (count-lines opoint end))
145 0 : (message "Page has %d lines (%d + %d)" total before after))))
146 :
147 : (defun what-page ()
148 : "Print page and line number of point."
149 : (interactive)
150 0 : (save-restriction
151 0 : (widen)
152 0 : (save-excursion
153 0 : (let ((count 1)
154 0 : (opoint (point)))
155 0 : (goto-char (point-min))
156 0 : (while (re-search-forward page-delimiter opoint t)
157 0 : (if (= (match-beginning 0) (match-end 0))
158 0 : (forward-char 1))
159 0 : (setq count (1+ count)))
160 0 : (message "Page %d, line %d" count (line-number-at-pos opoint))))))
161 :
162 :
163 :
164 : ;;; Place `provide' at end of file.
165 : (provide 'page)
166 :
167 : ;;; page.el ends here
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