lisp/view.el

   1 ;;; view.el --- peruse file or buffer without editing.
   2
   3 ;; Copyright (C) 1985, 1989 Free Software Foundation, Inc.
   4
   5 ;; Author: K. Shane Hartman
   6 ;; Maintainer: FSF
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This package provides the `view' major mode documented in the Emacs
  27 ;; user's manual.
  28
  29 ;;; Code:
  30
  31 (defvar view-mode-map nil)
  32 (if view-mode-map
  33     nil
  34   (setq view-mode-map (make-keymap))
  35   (fillarray (nth 1 view-mode-map) 'View-undefined)
  36   (define-key view-mode-map "\C-c" 'view-exit)
  37   (define-key view-mode-map "\C-z" 'suspend-emacs)
  38   (define-key view-mode-map "q" 'view-exit)
  39   (define-key view-mode-map "-" 'negative-argument)
  40   (define-key view-mode-map "0" 'digit-argument)
  41   (define-key view-mode-map "1" 'digit-argument)
  42   (define-key view-mode-map "2" 'digit-argument)
  43   (define-key view-mode-map "3" 'digit-argument)
  44   (define-key view-mode-map "4" 'digit-argument)
  45   (define-key view-mode-map "5" 'digit-argument)
  46   (define-key view-mode-map "6" 'digit-argument)
  47   (define-key view-mode-map "7" 'digit-argument)
  48   (define-key view-mode-map "8" 'digit-argument)
  49   (define-key view-mode-map "9" 'digit-argument)
  50   (define-key view-mode-map "\C-u" 'universal-argument)
  51   (define-key view-mode-map "\e" nil)
  52   (define-key view-mode-map "\C-x" 'Control-X-prefix)
  53   (define-key view-mode-map "\e-" 'negative-argument)
  54   (define-key view-mode-map "\e0" 'digit-argument)
  55   (define-key view-mode-map "\e1" 'digit-argument)
  56   (define-key view-mode-map "\e2" 'digit-argument)
  57   (define-key view-mode-map "\e3" 'digit-argument)
  58   (define-key view-mode-map "\e4" 'digit-argument)
  59   (define-key view-mode-map "\e5" 'digit-argument)
  60   (define-key view-mode-map "\e6" 'digit-argument)
  61   (define-key view-mode-map "\e7" 'digit-argument)
  62   (define-key view-mode-map "\e8" 'digit-argument)
  63   (define-key view-mode-map "\e9" 'digit-argument)
  64   (define-key view-mode-map "<" 'beginning-of-buffer)
  65   (define-key view-mode-map ">" 'end-of-buffer)
  66   (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
  67   (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
  68   (define-key view-mode-map " " 'View-scroll-lines-forward)
  69   (define-key view-mode-map "\177" 'View-scroll-lines-backward)
  70   (define-key view-mode-map "\n" 'View-scroll-one-more-line)
  71   (define-key view-mode-map "\r" 'View-scroll-one-more-line)
  72   (define-key view-mode-map "\C-l" 'recenter)
  73   (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
  74   (define-key view-mode-map "g" 'View-goto-line)
  75   (define-key view-mode-map "=" 'what-line)
  76   (define-key view-mode-map "." 'set-mark-command)
  77   (define-key view-mode-map "\C-@" 'set-mark-command)
  78   (define-key view-mode-map "'" 'View-back-to-mark)
  79   (define-key view-mode-map "@" 'View-back-to-mark)
  80   (define-key view-mode-map "x" 'exchange-point-and-mark)
  81   (define-key view-mode-map "h" 'Helper-describe-bindings)
  82   (define-key view-mode-map "?" 'Helper-describe-bindings)
  83   (define-key view-mode-map (char-to-string help-char) 'Helper-help)
  84   (define-key view-mode-map "\C-n" 'next-line)
  85   (define-key view-mode-map "\C-p" 'previous-line)
  86   (define-key view-mode-map "\C-s" 'isearch-forward)
  87   (define-key view-mode-map "\C-r" 'isearch-backward)
  88   (define-key view-mode-map "s" 'isearch-forward)
  89   (define-key view-mode-map "r" 'isearch-backward)
  90   (define-key view-mode-map "/" 'View-search-regexp-forward)
  91   (define-key view-mode-map "\\" 'View-search-regexp-backward)
  92   ;; This conflicts with the standard binding of isearch-regexp-forward
  93   (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
  94   (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)
  95   (define-key view-mode-map "n" 'View-search-last-regexp-forward)
  96   (define-key view-mode-map "p" 'View-search-last-regexp-backward)
  97   )
  98
  99
 100 ;;;###autoload
 101 (defun view-file (file-name)
 102   "View FILE in View mode, returning to previous buffer when done.
 103 The usual Emacs commands are not available; instead,
 104 a special set of commands (mostly letters and punctuation)
 105 are defined for moving around in the buffer.
 106 Space scrolls forward, Delete scrolls backward.
 107 For list of all View commands, type ? or h while viewing.
 108
 109 This command runs the normal hook `view-mode-hook'."
 110   (interactive "fView file: ")
 111   (let ((old-buf (current-buffer))
 112         (had-a-buf (get-file-buffer file-name))
 113         (buf-to-view (find-file-noselect file-name)))
 114     (switch-to-buffer buf-to-view t)
 115     (view-mode old-buf
 116                (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 117                     'kill-buffer))))
 118
 119 ;;;###autoload
 120 (defun view-file-other-window (file-name)
 121   "View FILE in View mode in other window.
 122 Return to previous buffer when done.
 123 The usual Emacs commands are not available; instead,
 124 a special set of commands (mostly letters and punctuation)
 125 are defined for moving around in the buffer.
 126 Space scrolls forward, Delete scrolls backward.
 127 For list of all View commands, type ? or h while viewing.
 128
 129 This command runs the normal hook `view-mode-hook'."
 130   (interactive "fView file: ")
 131   (let ((old-arrangement (current-window-configuration))
 132         (had-a-buf (get-file-buffer file-name))
 133         (buf-to-view (find-file-noselect file-name)))
 134     (switch-to-buffer-other-window buf-to-view)
 135     (view-mode old-arrangement
 136                (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 137                     'kill-buffer))))
 138
 139 ;;;###autoload
 140 (defun view-buffer (buffer-name)
 141   "View BUFFER in View mode, returning to previous buffer when done.
 142 The usual Emacs commands are not available; instead,
 143 a special set of commands (mostly letters and punctuation)
 144 are defined for moving around in the buffer.
 145 Space scrolls forward, Delete scrolls backward.
 146 For list of all View commands, type ? or h while viewing.
 147
 148 This command runs the normal hook `view-mode-hook'."
 149   (interactive "bView buffer: ")
 150   (let ((old-buf (current-buffer)))
 151     (switch-to-buffer buffer-name t)
 152     (view-mode old-buf nil)))
 153
 154 ;;;###autoload
 155 (defun view-buffer-other-window (buffer-name not-return)
 156   "View BUFFER in View mode in another window,
 157 returning to original buffer when done *only* if
 158 prefix argument NOT-RETURN is nil (which is the default).
 159
 160 The usual Emacs commands are not available in View mode; instead,
 161 a special set of commands (mostly letters and punctuation)
 162 are defined for moving around in the buffer.
 163 Space scrolls forward, Delete scrolls backward.
 164 For list of all View commands, type ? or h while viewing.
 165
 166 This command runs the normal hook `view-mode-hook'."
 167   (interactive "bView buffer:\nP")
 168   (let ((return-to (and not-return (current-window-configuration))))
 169     (switch-to-buffer-other-window buffer-name)
 170     (view-mode return-to)))
 171
 172 ;;;###autoload
 173 (defun view-mode (&optional prev-buffer action)
 174   "Major mode for viewing text but not editing it.
 175 Letters do not insert themselves.  Instead these commands are provided.
 176 Most commands take prefix arguments.  Commands dealing with lines
 177 default to \"scroll size\" lines (initially size of window).
 178 Search commands default to a repeat count of one.
 179 M-< or <        move to beginning of buffer.
 180 M-> or >        move to end of buffer.
 181 C-v or Space    scroll forward lines.
 182 M-v or DEL      scroll backward lines.
 183 CR or LF        scroll forward one line (backward with prefix argument).
 184 z               like Space except set number of lines for further
 185                    scrolling commands to scroll by.
 186 C-u and Digits  provide prefix arguments.  `-' denotes negative argument.
 187 =               prints the current line number.
 188 g               goes to line given by prefix argument.
 189 / or M-C-s      searches forward for regular expression
 190 \\ or M-C-r     searches backward for regular expression.
 191 n               searches forward for last regular expression.
 192 p               searches backward for last regular expression.
 193 C-@ or .        set the mark.
 194 x               exchanges point and mark.
 195 C-s or s        do forward incremental search.
 196 C-r or r        do reverse incremental search.
 197 @ or '          return to mark and pops mark ring.
 198                   Mark ring is pushed at start of every
 199                   successful search and when jump to line to occurs.
 200                   The mark is set on jump to buffer start or end.
 201 ? or h          provide help message (list of commands).
 202 \\[Helper-help]         provides help (list of commands or description of a command).
 203 C-n             moves down lines vertically.
 204 C-p             moves upward lines vertically.
 205 C-l             recenters the screen.
 206 q or C-c        exit view-mode and return to previous buffer.
 207
 208 Entry to this mode runs the normal hook `view-mode-hook'.
 209
 210 \\{view-mode-map}"
 211 ;  Not interactive because dangerous things happen
 212 ;  if you call it without passing a buffer as argument
 213 ;  and they are not easy to fix.
 214 ;  (interactive)
 215   (make-local-variable 'view-old-mode-line-buffer-identification)
 216   (setq view-old-mode-line-buffer-identification
 217         mode-line-buffer-identification)
 218   (make-local-variable 'view-old-buffer-read-only)
 219   (setq view-old-buffer-read-only buffer-read-only)
 220   (make-local-variable 'view-old-mode-name)
 221   (setq view-old-mode-name mode-name)
 222   (make-local-variable 'view-old-major-mode)
 223   (setq view-old-major-mode major-mode)
 224   (make-local-variable 'view-old-local-map)
 225   (setq view-old-local-map (current-local-map))
 226   (make-local-variable 'view-old-Helper-return-blurb)
 227   (setq view-old-Helper-return-blurb
 228         (and (boundp 'Helper-return-blurb) Helper-return-blurb))
 229
 230   (setq buffer-read-only t)
 231   (setq mode-line-buffer-identification
 232         (list
 233          (if (buffer-file-name)
 234              "Viewing %f"
 235            "Viewing %b")))
 236   (setq mode-name "View")
 237   (setq major-mode 'view-mode)
 238   (setq Helper-return-blurb
 239         (format "continue viewing %s"
 240                 (if (buffer-file-name)
 241                     (file-name-nondirectory (buffer-file-name))
 242                     (buffer-name))))
 243
 244   (make-local-variable 'view-exit-action)
 245   (setq view-exit-action action)
 246   (make-local-variable 'view-return-here)
 247   (setq view-return-here prev-buffer)
 248   (make-local-variable 'view-exit-position)
 249   (setq view-exit-position (point-marker))
 250
 251   (make-local-variable 'view-scroll-size)
 252   (setq view-scroll-size nil)
 253   (make-local-variable 'view-last-regexp)
 254   (setq view-last-regexp nil)
 255
 256   (beginning-of-line)
 257   (setq goal-column nil)
 258
 259   (use-local-map view-mode-map)
 260   (run-hooks 'view-hook 'view-mode-hook)
 261   (view-helpful-message))
 262
 263 \f
 264 (defun view-exit ()
 265   "Exit from view-mode.
 266 If you viewed an existing buffer, that buffer returns to its previous mode.
 267 If you viewed a file that was not present in Emacs, its buffer is killed."
 268   (interactive)
 269   (setq mode-line-buffer-identification
 270         view-old-mode-line-buffer-identification)
 271   (setq major-mode view-old-major-mode)
 272   (setq mode-name view-old-mode-name)
 273   (use-local-map view-old-local-map)
 274   (setq buffer-read-only view-old-buffer-read-only)
 275
 276   (goto-char view-exit-position)
 277   (set-marker view-exit-position nil)
 278
 279   ;; Now do something to the buffer that we were viewing
 280   ;; (such as kill it).
 281   (let ((viewed-buffer (current-buffer))
 282         (action view-exit-action))
 283     (cond
 284      ((bufferp view-return-here)
 285       (switch-to-buffer view-return-here))
 286      ((window-configuration-p view-return-here)
 287       (set-window-configuration view-return-here)))
 288     (if action (funcall action viewed-buffer))))
 289
 290 (defun view-helpful-message ()
 291   (message
 292      (substitute-command-keys
 293       "Type \\[Helper-help] for help, \\[Helper-describe-bindings] for commands, \\[view-exit] to quit.")))
 294
 295 (defun View-undefined ()
 296   (interactive)
 297   (ding)
 298   (view-helpful-message))
 299
 300 (defun view-window-size () (1- (window-height)))
 301
 302 (defun view-scroll-size ()
 303   (min (view-window-size) (or view-scroll-size (view-window-size))))
 304
 305 (defvar view-hook nil
 306   "Normal hook run when starting to view a buffer or file.")
 307
 308 (defvar view-mode-hook nil
 309   "Normal hook run when starting to view a buffer or file.")
 310
 311 ;(defun view-last-command (&optional who what)
 312 ;  (setq view-last-command-entry this-command)
 313 ;  (setq view-last-command who)
 314 ;  (setq view-last-command-argument what))
 315
 316 ;(defun View-repeat-last-command ()
 317 ;  "Repeat last command issued in View mode."
 318 ;  (interactive)
 319 ;  (if (and view-last-command
 320 ;          (eq view-last-command-entry last-command))
 321 ;      (funcall view-last-command view-last-command-argument))
 322 ;  (setq this-command view-last-command-entry))
 323
 324 (defun View-goto-line (&optional line)
 325   "Move to line LINE in View mode.
 326 Display is centered at LINE.  Sets mark at starting position and pushes
 327 mark ring."
 328   (interactive "p")
 329   (push-mark)
 330   (goto-line (or line 1))
 331   (recenter (/ (view-window-size) 2)))
 332
 333 (defun View-scroll-lines-forward (&optional lines)
 334   "Scroll forward in View mode, or exit if end of text is visible.
 335 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 336 Arg is number of lines to scroll."
 337   (interactive "P")
 338   (if (and (pos-visible-in-window-p (point-max))
 339            ;; Allow scrolling backward at the end of the buffer.
 340            (or (null lines)
 341                (> lines 0)))
 342       (view-exit)
 343     (setq lines
 344           (if lines (prefix-numeric-value lines)
 345             (view-scroll-size)))
 346     ;; (view-last-command 'View-scroll-lines-forward lines)
 347     (if (>= lines (view-window-size))
 348         (scroll-up nil)
 349       (if (>= (- lines) (view-window-size))
 350           (scroll-down nil)
 351         (scroll-up lines)))
 352     (cond ((pos-visible-in-window-p (point-max))
 353            (goto-char (point-max))
 354            (recenter -1)
 355            (message (substitute-command-keys
 356                      "End.  Type \\[view-exit] to quit viewing."))))
 357     (move-to-window-line -1)
 358     (beginning-of-line)))
 359
 360 (defun View-scroll-lines-forward-set-scroll-size (&optional lines)
 361   "Scroll forward LINES lines in View mode, setting the \"scroll size\".
 362 This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
 363 The absolute value of LINES is used, so this command can be used to scroll
 364 backwards (but \"scroll size\" is always positive).  If LINES is greater than
 365 window height or omitted, then window height is assumed.  If LINES is less
 366 than window height then scrolling context is provided from previous screen."
 367   (interactive "P")
 368   (if (not lines)
 369       (setq view-scroll-size (view-window-size))
 370     (setq lines (prefix-numeric-value lines))
 371     (setq view-scroll-size
 372           (min (if (> lines 0) lines (- lines)) (view-window-size))))
 373   (View-scroll-lines-forward lines))
 374
 375 (defun View-scroll-one-more-line (&optional arg)
 376   "Scroll one more line up in View mode.
 377 With ARG scroll one line down."
 378   (interactive "P")
 379   (View-scroll-lines-forward (if (not arg) 1 -1)))
 380
 381 (defun View-scroll-lines-backward (&optional lines)
 382   "Scroll backward in View mode.
 383 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 384 Arg is number of lines to scroll."
 385   (interactive "P")
 386   (View-scroll-lines-forward (if lines
 387                                  (- (prefix-numeric-value lines))
 388                                (- (view-scroll-size)))))
 389
 390 (defun View-search-regexp-forward (n regexp)
 391   "Search forward for Nth occurrence of REGEXP.
 392 Displays line found at center of window.  REGEXP is remembered for
 393 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring."
 394   (interactive "p\nsSearch forward (regexp): ")
 395   (if (> (length regexp) 0)
 396       (progn
 397        ;(view-last-command 'View-search-last-regexp-forward n)
 398         (view-search n regexp))))
 399
 400 (defun View-search-regexp-backward (n regexp)
 401   "Search backward from window start for Nth instance of REGEXP.
 402 Displays line found at center of window.  REGEXP is remembered for
 403 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring."
 404   (interactive "p\nsSearch backward (regexp): ")
 405   (View-search-regexp-forward (- n) regexp))
 406
 407 (defun View-search-last-regexp-forward (n)
 408   "Search forward from window end for Nth instance of last regexp.
 409 Displays line found at center of window.  Sets mark at starting position
 410 and pushes mark ring."
 411   (interactive "p")
 412   (View-search-regexp-forward n view-last-regexp))
 413
 414 (defun View-search-last-regexp-backward (n)
 415   "Search backward from window start for Nth instance of last regexp.
 416 Displays line found at center of window.  Sets mark at starting position and
 417 pushes mark ring."
 418   (interactive "p")
 419   (View-search-regexp-backward n view-last-regexp))
 420
 421 (defun View-back-to-mark (&optional ignore)
 422   "Return to last mark set in View mode, else beginning of file.
 423 Displays line at center of window.  Pops mark ring so successive
 424 invocations return to earlier marks."
 425   (interactive)
 426   (goto-char (or (mark) (point-min)))
 427   (pop-mark)
 428   (recenter (/ (view-window-size) 2)))
 429
 430 (defun view-search (times regexp)
 431   (setq view-last-regexp regexp)
 432   (let (where)
 433     (save-excursion
 434       (move-to-window-line (if (< times 0) 0 -1))
 435       (if (re-search-forward regexp nil t times)
 436           (setq where (point))))
 437     (if where
 438         (progn
 439           (push-mark)
 440           (goto-char where)
 441           (beginning-of-line)
 442           (recenter (/ (view-window-size) 2)))
 443       (message "Can't find occurrence %d of %s" times regexp)
 444       (sit-for 4))))
 445
 446 \f
 447 (provide 'view)
 448
 449 ;;; view.el ends here