1 ;;; view-less.el --- Minor mode for browsing files with keybindings like `less'
3 ;; Copyright (C) 1994, 1995 Tinker Systems and INS Engineering Corp.
5 ;; Author: Jonathan Stigelman <stig@hackvan.com>
6 ;; Maintainer: XEmacs Development Team
9 ;; This file is part of XEmacs.
11 ;; XEmacs 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 2 of the License, or
14 ;; (at your option) any later version.
16 ;; XEmacs 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.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with XEmacs; if not, write to the Free Software
23 ;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 ;;; Synched up with: Not in FSF.
29 ;; This mode is for browsing files without changing them. Keybindings
30 ;; similar to those used by the less(1) program are used.
32 ;; Originally written for v18 by David Gudeman (gudeman@arizona.edu)
33 ;; Mods by Bengt Martensson, to closely resemble less (July 1987)
35 ;; If you would like all write-protected files to be visited in view-mode,
36 ;; then add the following to your .emacs file:
38 ;; (add-hook 'find-file-hooks 'auto-view-mode)
42 (defvar view-search-string ""
43 "Last string searched for with view-search functions.")
45 (defvar view-search-arg 1
46 "Argument to last view search.")
48 (defvar view-default-lines 10
49 "Default value for the \"d\" and \"u\" commands in view-mode")
51 (defvar view-minor-mode nil
52 "Non-nil when view-mode is active. Call `view-mode' to toggle.")
53 (make-variable-buffer-local 'view-minor-mode)
56 (defvar view-minor-mode-map
57 (let ((map (make-keymap)))
58 (set-keymap-name map 'view-minor-mode-map)
60 (define-key map "-" 'negative-argument)
61 (define-key map " " 'scroll-up)
62 (define-key map "f" 'scroll-up)
63 (define-key map "b" 'scroll-down)
64 (define-key map 'backspace 'scroll-down)
65 (define-key map 'delete 'scroll-down)
66 (define-key map "\r" 'view-scroll-lines-up)
67 (define-key map "\n" 'view-scroll-lines-up)
68 (define-key map "e" 'view-scroll-lines-up)
69 (define-key map "j" 'view-scroll-lines-up)
70 (define-key map "y" 'view-scroll-lines-down)
71 (define-key map "k" 'view-scroll-lines-down)
72 (define-key map "d" 'view-scroll-some-lines-up)
73 (define-key map "u" 'view-scroll-some-lines-down)
74 (define-key map "r" 'recenter)
75 (define-key map "t" 'toggle-truncate-lines)
76 (define-key map "N" 'view-buffer)
77 (define-key map "E" 'view-file)
78 (define-key map "P" 'view-buffer)
79 (define-key map "!" 'shell-command)
80 (define-key map "|" 'shell-command-on-region)
81 (define-key map "=" 'what-line)
82 (define-key map "?" 'view-search-backward)
83 (define-key map "h" 'view-mode-describe)
84 (define-key map "s" 'view-repeat-search)
85 (define-key map "n" 'view-repeat-search)
86 (define-key map "/" 'view-search-forward)
87 (define-key map "\\" 'view-search-backward)
88 (define-key map "g" 'view-goto-line)
89 (define-key map "G" 'view-last-windowful)
90 (define-key map "%" 'view-goto-percent)
91 (define-key map "p" 'view-goto-percent)
92 (define-key map "m" 'point-to-register)
93 (define-key map "'" 'register-to-point)
94 (define-key map "C" 'view-cleanup-backspaces)
95 (define-key map "\C-c\C-c" 'view-quit)
96 ;; #### - should this use substitute-command-keys?
97 (define-key map "\C-x\C-q" 'view-quit-toggle-ro)
98 (define-key map "q" 'view-quit)
102 (add-minor-mode 'view-minor-mode " View" view-minor-mode-map)
105 (defvar view-mode-map
106 (let ((map (copy-keymap view-minor-mode-map)))
107 (set-keymap-name map 'view-mode-map)
111 (defun view-file (file &optional other-p)
112 "Find FILE, enter view mode. With prefix arg OTHER-P, use other window."
113 (interactive "fView File: \nP")
114 (let ((old-p (get-file-buffer file))
115 (obuf (current-buffer)))
117 (find-file-other-window file)
119 (view-mode (if other-p nil obuf)
120 (if old-p nil 'kill-buffer))
124 (defun view-buffer (buf &optional other-p)
125 "Switch to BUF, enter view mode. With prefix arg use other window."
126 (interactive "bView Buffer: \nP")
127 (let ((obuf (current-buffer)))
129 (switch-to-buffer-other-window buf)
130 (switch-to-buffer buf))
131 (view-mode (if other-p nil obuf) (if other-p nil 'bury-buffer))))
134 (defun view-file-other-window (file)
135 "Find FILE in other window, and enter view mode."
136 (interactive "fView File: ")
140 (defun view-buffer-other-window (buffer)
141 "Switch to BUFFER in another window, and enter view mode."
142 (interactive "bView Buffer: ")
143 (view-buffer buffer t))
145 (defun view-brief-help ()
147 (substitute-command-keys
148 "\\<view-minor-mode-map>\\[scroll-up] = page forward; \\[scroll-down] = page back; \
149 \\[view-mode-describe] = help; \\[view-quit] = quit.")))
151 (defvar view-major-mode)
152 (defvar view-exit-position)
153 (defvar view-prev-buffer)
154 (defvar view-exit-action)
155 (defvar view-old-buffer-read-only)
158 (defun view-minor-mode (&optional prev-buffer exit-action)
159 "Minor mode for viewing text, with bindings like `less'.
161 \\<view-minor-mode-map>
164 \\[scroll-up] page forward
165 \\[scroll-down] page back
166 \\[view-scroll-lines-up] scroll prefix-arg lines forward, default 1.
167 \\[view-scroll-lines-down] scroll prefix-arg lines backward, default 1.
168 \\[view-scroll-some-lines-down] scroll prefix-arg lines backward, default 10.
169 \\[view-scroll-some-lines-up] scroll prefix-arg lines forward, default 10.
170 \\[what-line] print line number
171 \\[view-mode-describe] print this help message
172 \\[view-search-forward] regexp search, uses previous string if you just hit RET
173 \\[view-search-backward] as above but searches backward
174 \\[view-repeat-search] repeat last search
175 \\[view-goto-line] goto line prefix-arg, default 1
176 \\[view-last-windowful] goto line prefix-arg, default last line
177 \\[view-goto-percent] goto a position by percentage
178 \\[toggle-truncate-lines] toggle truncate-lines
179 \\[view-file] view another file
180 \\[view-buffer] view another buffer
181 \\[view-cleanup-backspaces] cleanup backspace constructions
182 \\[shell-command] execute a shell command
183 \\[shell-command-on-region]\
184 execute a shell command with the region as input
185 \\[view-quit] exit view-mode, and bury the current buffer.
187 If invoked with the optional (prefix) arg non-nil, view-mode cleans up
188 backspace constructions.
191 \\{view-minor-mode-map}"
194 (make-local-variable 'view-default-lines)
195 (set (make-local-variable 'view-exit-position) (point))
196 (set (make-local-variable 'view-prev-buffer) prev-buffer)
197 (set (make-local-variable 'view-exit-action) exit-action)
198 (set (make-local-variable 'view-old-buffer-read-only) buffer-read-only)
199 (add-hook (make-local-variable 'change-major-mode-hook)
200 'view-fixup-read-only)
201 (setq view-minor-mode t
206 (defun view-mode (&optional prev-buffer exit-action clean-bs)
207 "View the current buffer using view-minor-mode. This exists to be 99.9%
208 compatible with the implementations of `view-mode' in view.el and older
209 versions of view-less.el."
210 (interactive (list nil 'bury-buffer current-prefix-arg))
211 ;; #### - The first two arguments provide compatibility with view.el (and
212 ;; thus FSFmacs), while the third argument as a prefix argument maintains
213 ;; interactive compatibility with older versions of view-less. --Stig
214 (if clean-bs (cleanup-backspaces))
215 (view-minor-mode prev-buffer exit-action))
218 (defun view-major-mode (&optional prev-buffer exit-action clean-bs)
219 "View the current buffer using view-mode, as a major mode.
220 This function has a nonstandard name because `view-mode' is wrongly
221 named but is like this for compatibility reasons."
222 ;; #### - The first two arguments provide compatibility with view.el (and
223 ;; thus FSFmacs), while the third argument as a prefix argument maintains
224 ;; interactive compatibility with older versions of view-less. --Stig
225 (interactive (list nil 'bury-buffer current-prefix-arg))
226 (kill-all-local-variables)
227 (use-local-map view-mode-map)
228 (setq major-mode 'view-mode)
229 (set (make-local-variable 'view-exit-position) (point))
230 (set (make-local-variable 'view-prev-buffer) prev-buffer)
231 (set (make-local-variable 'view-exit-action) exit-action)
232 (set (make-local-variable 'view-old-buffer-read-only) buffer-read-only)
233 (set (make-local-variable 'view-major-mode) t)
234 (setq buffer-read-only t)
235 (if clean-bs (cleanup-backspaces))
236 (run-hooks 'view-mode-hook))
239 (defun auto-view-mode ()
240 "If the file of the current buffer is not writable, call view-mode.
241 This is meant to be added to `find-file-hooks'."
242 (or (file-writable-p buffer-file-name)
245 (defun view-fixup-read-only ()
246 ;; doing M-x normal mode should NOT leave the buffer read-only
247 (and (boundp 'view-old-buffer-read-only)
248 (progn (setq buffer-read-only view-old-buffer-read-only)
249 (kill-local-variable 'view-old-buffer-read-only))))
251 (defun view-quit-toggle-ro ()
252 "Exit view mode and execute the global binding of the key that invoked this
253 command. Normally, this will toggle the state of `buffer-read-only', perhaps
254 invoking some version-control mechanism."
256 (setq view-exit-position nil)
257 ;; Kludge so this works as advertised. Stig, why can't you write
259 (let ((buffer-read-only buffer-read-only))
261 ;; no longer in view-minor-mode, so the keymap has changed...
262 (call-interactively (key-binding (this-command-keys))))
264 (defun view-quit (&optional no-exit-action)
265 "Exit view mode. With prefix argument, keep the current buffer selected."
267 (view-fixup-read-only)
268 (setq view-minor-mode nil)
269 (if view-exit-position (goto-char view-exit-position))
270 (if (and (boundp 'view-major-mode) view-major-mode)
272 (let ((pbuf view-prev-buffer)
273 (exitact view-exit-action))
276 (if exitact (funcall exitact (current-buffer)))
277 (if pbuf (switch-to-buffer pbuf))))))
279 ;; #### - similar to what's in man.el and this ought to be written in C anyway... --Stig
280 (defun cleanup-backspaces ()
281 "Cleanup backspace constructions.
282 _^H and ^H_ sequences are deleted. x^Hx sequences are turned into x for all
283 characters x. ^^H| and |^H^ sequences are turned into ^. +^Ho and o^H+ are
287 (goto-char (point-min))
288 (while (= (following-char) ?\C-h)
290 (while (search-forward "\C-h" nil t)
292 (cond ((looking-at "_\C-h\\|\\(.\\)\C-h\\1\\||\C-h\\^")
294 ((looking-at ".\C-h_\\|\\^\C-h|")
297 ((looking-at "+\C-ho\\|o\C-h+")
300 ((looking-at "|\C-h-")
303 (t (forward-char 2))))))
305 (defun view-cleanup-backspaces ()
306 "Cleanup backspaces and if buffer is currently unmodified, don't flag it
307 as a modified buffer. This works even if the buffer is read-only."
309 (let ((buffer-read-only)
310 (buf-mod (buffer-modified-p)))
312 ;; #### - THIS IS PROBABLY A REALLY DANGEROUS THING TO DO IN A MINOR MODE!!
313 (set-buffer-modified-p buf-mod)))
316 (defun toggle-truncate-lines (&optional p)
317 "Toggles the values of truncate-lines.
318 Positive prefix arg sets, negative disables."
320 (setq truncate-lines (if p
321 (> (prefix-numeric-value p) 0)
322 (not truncate-lines)))
325 (defun view-scroll-lines-up (p)
326 "Scroll up prefix-arg lines, default 1."
330 (defun view-scroll-lines-down (p)
331 "Scroll down prefix-arg lines, default 1."
335 (defun view-scroll-some-lines-down (&optional n)
336 "Scroll down prefix-arg lines, default 10, or last argument."
338 (if (> n 1) (setq view-default-lines n))
339 (scroll-down view-default-lines))
341 (defun view-scroll-some-lines-up (&optional n)
342 "Scroll up prefix-arg lines, default 10, or last argument."
344 (if (> n 1) (setq view-default-lines n))
345 (scroll-up view-default-lines))
347 (defun view-goto-line (&optional n)
348 "Goto prefix arg line N. N = 1 by default.."
352 (defun view-last-windowful (&optional n)
353 "Goto prefix arg line N or the first line of the last windowful in buffer."
355 (if current-prefix-arg
359 (move-to-window-line 0)))
361 (defun view-goto-percent (&optional percent)
362 "Set mark and go to a position PERCENT way into the current buffer."
364 (set-mark-command nil)
365 (goto-char (+ (point-min) (/ (* percent (- (point-max) (point-min))) 100)))
368 (defun view-mode-describe ()
370 (let ((mode-name "View")
371 (major-mode 'view-mode))
374 (defun view-search-forward (s p)
375 "Search forward for REGEXP. If regexp is empty, use last search string.
376 With prefix ARG, search forward that many occurrences."
377 (interactive "sView search: \np")
380 (if (string-equal "" s) view-search-string s) nil nil p)
381 (setq view-search-arg p)
382 (or (string-equal "" s)
383 (setq view-search-string s))))
385 (defun view-search-backward (s p)
386 "Search backward for REGEXP. If regexp is empty, use last search string.
387 With prefix ARG, search forward that many occurrences."
388 (interactive "sView search backward: \np")
389 (view-search-forward s (- p)))
391 (defun view-repeat-search (p)
392 "Repeat last view search command. If a prefix arg is given, use that
393 instead of the previous arg, if the prefix is just a -, then take the
394 negative of the last prefix arg."
398 (cond ((null p) view-search-arg)
399 ((eq p '-) (- view-search-arg))
400 (t (prefix-numeric-value p)))))
405 ;;; view-less.el ends here