lisp/view.el

   1 ;;; view.el --- peruse file or buffer without editing.
   2
   3 ;; Author: K. Shane Hartman
   4 ;; Maintainer: FSF
   5 ;; Last-Modified: 21 Aug 1988
   6
   7 ;; Copyright (C) 1985, 1989 Free Software Foundation, Inc.
   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 2, or (at your option)
  14 ;; 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; see the file COPYING.  If not, write to
  23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Code:
  26
  27 (defvar view-mode-map nil)
  28 (if view-mode-map
  29     nil
  30   (setq view-mode-map (make-keymap))
  31   (fillarray (nth 1 view-mode-map) 'View-undefined)
  32   (define-key view-mode-map "\C-c" 'view-exit)
  33   (define-key view-mode-map "\C-z" 'suspend-emacs)
  34   (define-key view-mode-map "q" 'view-exit)
  35   (define-key view-mode-map "-" 'negative-argument)
  36   (define-key view-mode-map "0" 'digit-argument)
  37   (define-key view-mode-map "1" 'digit-argument)
  38   (define-key view-mode-map "2" 'digit-argument)
  39   (define-key view-mode-map "3" 'digit-argument)
  40   (define-key view-mode-map "4" 'digit-argument)
  41   (define-key view-mode-map "5" 'digit-argument)
  42   (define-key view-mode-map "6" 'digit-argument)
  43   (define-key view-mode-map "7" 'digit-argument)
  44   (define-key view-mode-map "8" 'digit-argument)
  45   (define-key view-mode-map "9" 'digit-argument)
  46   (define-key view-mode-map "\C-u" 'universal-argument)
  47   (define-key view-mode-map "\e" nil)
  48   (define-key view-mode-map "\C-x" 'Control-X-prefix)
  49   (define-key view-mode-map "\e-" 'negative-argument)
  50   (define-key view-mode-map "\e0" 'digit-argument)
  51   (define-key view-mode-map "\e1" 'digit-argument)
  52   (define-key view-mode-map "\e2" 'digit-argument)
  53   (define-key view-mode-map "\e3" 'digit-argument)
  54   (define-key view-mode-map "\e4" 'digit-argument)
  55   (define-key view-mode-map "\e5" 'digit-argument)
  56   (define-key view-mode-map "\e6" 'digit-argument)
  57   (define-key view-mode-map "\e7" 'digit-argument)
  58   (define-key view-mode-map "\e8" 'digit-argument)
  59   (define-key view-mode-map "\e9" 'digit-argument)
  60   (define-key view-mode-map "<" 'beginning-of-buffer)
  61   (define-key view-mode-map ">" 'end-of-buffer)
  62   (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
  63   (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
  64   (define-key view-mode-map " " 'View-scroll-lines-forward)
  65   (define-key view-mode-map "\177" 'View-scroll-lines-backward)
  66   (define-key view-mode-map "\n" 'View-scroll-one-more-line)
  67   (define-key view-mode-map "\r" 'View-scroll-one-more-line)
  68   (define-key view-mode-map "\C-l" 'recenter)
  69   (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
  70   (define-key view-mode-map "g" 'View-goto-line)
  71   (define-key view-mode-map "=" 'what-line)
  72   (define-key view-mode-map "." 'set-mark-command)
  73   (define-key view-mode-map "\C-@" 'set-mark-command)
  74   (define-key view-mode-map "'" 'View-back-to-mark)
  75   (define-key view-mode-map "@" 'View-back-to-mark)
  76   (define-key view-mode-map "x" 'exchange-point-and-mark)
  77   (define-key view-mode-map "h" 'Helper-describe-bindings)
  78   (define-key view-mode-map "?" 'Helper-describe-bindings)
  79   (define-key view-mode-map "\C-h" 'Helper-help)
  80   (define-key view-mode-map "\C-n" 'next-line)
  81   (define-key view-mode-map "\C-p" 'previous-line)
  82   (define-key view-mode-map "\C-s" 'isearch-forward)
  83   (define-key view-mode-map "\C-r" 'isearch-backward)
  84   (define-key view-mode-map "s" 'isearch-forward)
  85   (define-key view-mode-map "r" 'isearch-backward)
  86   (define-key view-mode-map "/" 'View-search-regexp-forward)
  87   (define-key view-mode-map "\\" 'View-search-regexp-backward)
  88   ;; This conflicts with the standard binding of isearch-regexp-forward
  89   (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
  90   (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)
  91   (define-key view-mode-map "n" 'View-search-last-regexp-forward)
  92   (define-key view-mode-map "p" 'View-search-last-regexp-backward)
  93   )
  94
  95
  96 ;;;###autoload
  97 (defun view-file (file-name)
  98   "View FILE in View mode, returning to previous buffer when done.
  99 The usual Emacs commands are not available; instead,
 100 a special set of commands (mostly letters and punctuation)
 101 are defined for moving around in the buffer.
 102 Space scrolls forward, Delete scrolls backward.
 103 For list of all View commands, type ? or h while viewing.
 104
 105 Calls the value of  view-hook  if that is non-nil."
 106   (interactive "fView file: ")
 107   (let ((old-buf (current-buffer))
 108         (had-a-buf (get-file-buffer file-name))
 109         (buf-to-view (find-file-noselect file-name)))
 110     (switch-to-buffer buf-to-view t)
 111     (view-mode old-buf
 112                (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 113                     'kill-buffer))))
 114
 115 ;;;###autoload
 116 (defun view-file-other-window (file-name)
 117   "View FILE in View mode in other window.
 118 Return to previous buffer when done.
 119 The usual Emacs commands are not available; instead,
 120 a special set of commands (mostly letters and punctuation)
 121 are defined for moving around in the buffer.
 122 Space scrolls forward, Delete scrolls backward.
 123 For list of all View commands, type ? or h while viewing.
 124
 125 Calls the value of  view-hook  if that is non-nil."
 126   (interactive "fView file: ")
 127   (let ((old-arrangement (current-window-configuration))
 128         (had-a-buf (get-file-buffer file-name))
 129         (buf-to-view (find-file-noselect file-name)))
 130     (switch-to-buffer-other-window buf-to-view)
 131     (view-mode old-arrangement
 132                (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 133                     'kill-buffer))))
 134
 135 ;;;###autoload
 136 (defun view-buffer (buffer-name)
 137   "View BUFFER in View mode, returning to previous buffer when done.
 138 The usual Emacs commands are not available; instead,
 139 a special set of commands (mostly letters and punctuation)
 140 are defined for moving around in the buffer.
 141 Space scrolls forward, Delete scrolls backward.
 142 For list of all View commands, type ? or h while viewing.
 143
 144 Calls the value of  view-hook  if that is non-nil."
 145   (interactive "bView buffer: ")
 146   (let ((old-buf (current-buffer)))
 147     (switch-to-buffer buffer-name t)
 148     (view-mode old-buf nil)))
 149
 150 ;;;###autoload
 151 (defun view-buffer-other-window (buffer-name not-return)
 152   "View BUFFER in View mode in another window,
 153 returning to original buffer when done  ONLY if
 154 prefix argument not-return is nil (as by default).
 155   The usual Emacs commands are not available; instead,
 156 a special set of commands (mostly letters and punctuation)
 157 are defined for moving around in the buffer.
 158 Space scrolls forward, Delete scrolls backward.
 159 For list of all View commands, type ? or h while viewing.
 160
 161 Calls the value of  view-hook  if that is non-nil."
 162   (interactive \"bView buffer:\\nP\")
 163   (let ((return-to (and not-return (current-window-configuration))))
 164     (switch-to-buffer-other-window buffer-name)
 165     (view-mode return-to)))
 166
 167 ;;;###autoload
 168 (defun view-mode (&optional prev-buffer action)
 169   "Major mode for viewing text but not editing it.
 170 Letters do not insert themselves.  Instead these commands are provided.
 171 Most commands take prefix arguments.  Commands dealing with lines
 172 default to \"scroll size\" lines (initially size of window).
 173 Search commands default to a repeat count of one.
 174 M-< or <        move to beginning of buffer.
 175 M-> or >        move to end of buffer.
 176 C-v or Space    scroll forward lines.
 177 M-v or DEL      scroll backward lines.
 178 CR or LF        scroll forward one line (backward with prefix argument).
 179 z               like Space except set number of lines for further
 180                    scrolling commands to scroll by.
 181 C-u and Digits  provide prefix arguments.  `-' denotes negative argument.
 182 =               prints the current line number.
 183 g               goes to line given by prefix argument.
 184 / or M-C-s      searches forward for regular expression
 185 \\ or M-C-r     searches backward for regular expression.
 186 n               searches forward for last regular expression.
 187 p               searches backward for last regular expression.
 188 C-@ or .        set the mark.
 189 x               exchanges point and mark.
 190 C-s or s        do forward incremental search.
 191 C-r or r        do reverse incremental search.
 192 @ or '          return to mark and pops mark ring.
 193                   Mark ring is pushed at start of every
 194                   successful search and when jump to line to occurs.
 195                   The mark is set on jump to buffer start or end.
 196 ? or h          provide help message (list of commands).
 197 C-h             provides help (list of commands or description of a command).
 198 C-n             moves down lines vertically.
 199 C-p             moves upward lines vertically.
 200 C-l             recenters the screen.
 201 q or C-c        exit view-mode and return to previous buffer.
 202
 203 Entry to this mode calls the value of  view-hook  if non-nil.
 204 \\{view-mode-map}"
 205 ;  Not interactive because dangerous things happen
 206 ;  if you call it without passing a buffer as argument
 207 ;  and they are not easy to fix.
 208 ;  (interactive)
 209   (make-local-variable 'view-old-mode-line-buffer-identification)
 210   (setq view-old-mode-line-buffer-identification
 211         mode-line-buffer-identification)
 212   (make-local-variable 'view-old-buffer-read-only)
 213   (setq view-old-buffer-read-only buffer-read-only)
 214   (make-local-variable 'view-old-mode-name)
 215   (setq view-old-mode-name mode-name)
 216   (make-local-variable 'view-old-major-mode)
 217   (setq view-old-major-mode major-mode)
 218   (make-local-variable 'view-old-local-map)
 219   (setq view-old-local-map (current-local-map))
 220   (make-local-variable 'view-old-Helper-return-blurb)
 221   (setq view-old-Helper-return-blurb
 222         (and (boundp 'Helper-return-blurb) Helper-return-blurb))
 223
 224   (setq buffer-read-only t)
 225   (setq mode-line-buffer-identification
 226         (list
 227          (if (buffer-file-name)
 228              "Viewing %f"
 229            "Viewing %b")))
 230   (setq mode-name "View")
 231   (setq major-mode 'view-mode)
 232   (setq Helper-return-blurb
 233         (format "continue viewing %s"
 234                 (if (buffer-file-name)
 235                     (file-name-nondirectory (buffer-file-name))
 236                     (buffer-name))))
 237
 238   (make-local-variable 'view-exit-action)
 239   (setq view-exit-action action)
 240   (make-local-variable 'view-return-here)
 241   (setq view-return-here prev-buffer)
 242   (make-local-variable 'view-exit-position)
 243   (setq view-exit-position (point-marker))
 244
 245   (make-local-variable 'view-scroll-size)
 246   (setq view-scroll-size nil)
 247   (make-local-variable 'view-last-regexp)
 248   (setq view-last-regexp nil)
 249
 250   (beginning-of-line)
 251   (setq goal-column nil)
 252
 253   (use-local-map view-mode-map)
 254   (run-hooks 'view-hook)
 255   (view-helpful-message))
 256
 257 \f
 258 (defun view-exit ()
 259   "Exit from view-mode.
 260 If you viewed an existing buffer, that buffer returns to its previous mode.
 261 If you viewed a file that was not present in Emacs, its buffer is killed."
 262   (interactive)
 263   (setq mode-line-buffer-identification
 264         view-old-mode-line-buffer-identification)
 265   (setq major-mode view-old-major-mode)
 266   (setq mode-name view-old-mode-name)
 267   (use-local-map (current-local-map))
 268   (setq buffer-read-only view-old-buffer-read-only)
 269
 270   (goto-char view-exit-position)
 271   (set-marker view-exit-position nil)
 272
 273   ;; Now do something to the buffer that we were viewing
 274   ;; (such as kill it).
 275   (let ((viewed-buffer (current-buffer))
 276         (action view-exit-action))
 277     (cond
 278      ((bufferp view-return-here)
 279       (switch-to-buffer view-return-here))
 280      ((window-configuration-p view-return-here)
 281       (set-window-configuration view-return-here)))
 282     (if action (funcall action viewed-buffer))))
 283
 284 (defun view-helpful-message ()
 285   (message
 286    (if (and (eq (key-binding "\C-h") 'Helper-help)
 287             (eq (key-binding "?") 'Helper-describe-bindings)
 288             (eq (key-binding "\C-c") 'view-exit))
 289        "Type C-h for help, ? for commands, C-c to quit"
 290      (substitute-command-keys
 291       "Type \\[Helper-help] for help, \\[Helper-describe-bindings] for commands, \\[exit-recursive-edit] to quit."))))
 292
 293 (defun View-undefined ()
 294   (interactive)
 295   (ding)
 296   (view-helpful-message))
 297
 298 (defun view-window-size () (1- (window-height)))
 299
 300 (defun view-scroll-size ()
 301   (min (view-window-size) (or view-scroll-size (view-window-size))))
 302
 303 (defvar view-hook nil
 304   "If non-nil, its value is called when viewing buffer or file.")
 305
 306 ;(defun view-last-command (&optional who what)
 307 ;  (setq view-last-command-entry this-command)
 308 ;  (setq view-last-command who)
 309 ;  (setq view-last-command-argument what))
 310
 311 ;(defun View-repeat-last-command ()
 312 ;  "Repeat last command issued in View mode."
 313 ;  (interactive)
 314 ;  (if (and view-last-command
 315 ;          (eq view-last-command-entry last-command))
 316 ;      (funcall view-last-command view-last-command-argument))
 317 ;  (setq this-command view-last-command-entry))
 318
 319 (defun View-goto-line (&optional line)
 320   "Move to LINE in View mode.
 321 Display is centered at LINE.  Sets mark at starting position and pushes
 322 mark ring."
 323   (interactive "p")
 324   (push-mark)
 325   (goto-line (or line 1))
 326   (recenter (/ (view-window-size) 2)))
 327
 328 (defun View-scroll-lines-forward (&optional lines)
 329   "Scroll forward in View mode, or exit if end of text is visible.
 330 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 331 Arg is number of lines to scroll."
 332   (interactive "P")
 333   (if (pos-visible-in-window-p (point-max))
 334       (exit-recursive-edit))
 335   (setq lines
 336         (if lines (prefix-numeric-value lines)
 337           (view-scroll-size)))
 338 ; (view-last-command 'View-scroll-lines-forward lines)
 339   (if (>= lines (view-window-size))
 340       (scroll-up nil)
 341     (if (>= (- lines) (view-window-size))
 342         (scroll-down nil)
 343       (scroll-up lines)))
 344   (cond ((pos-visible-in-window-p (point-max))
 345          (goto-char (point-max))
 346          (recenter -1)
 347          (message (substitute-command-keys
 348                 "End.  Type \\[exit-recursive-edit] to quit viewing."))))
 349   (move-to-window-line -1)
 350   (beginning-of-line))
 351
 352 (defun View-scroll-lines-forward-set-scroll-size (&optional lines)
 353   "Scroll forward LINES lines in View mode, setting the \"scroll size\".
 354 This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
 355 The absolute value of LINES is used, so this command can be used to scroll
 356 backwards (but \"scroll size\" is always positive).  If LINES is greater than
 357 window height or omitted, then window height is assumed.  If LINES is less
 358 than window height then scrolling context is provided from previous screen."
 359   (interactive "P")
 360   (if (not lines)
 361       (setq view-scroll-size (view-window-size))
 362     (setq lines (prefix-numeric-value lines))
 363     (setq view-scroll-size
 364           (min (if (> lines 0) lines (- lines)) (view-window-size))))
 365   (View-scroll-lines-forward lines))
 366
 367 (defun View-scroll-one-more-line (&optional arg)
 368   "Scroll one more line up in View mode.
 369 With ARG scroll one line down."
 370   (interactive "P")
 371   (View-scroll-lines-forward (if (not arg) 1 -1)))
 372
 373 (defun View-scroll-lines-backward (&optional lines)
 374   "Scroll backward in View mode.
 375 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 376 Arg is number of lines to scroll."
 377   (interactive "P")
 378   (View-scroll-lines-forward (if lines
 379                                  (- (prefix-numeric-value lines))
 380                                (- (view-scroll-size)))))
 381
 382 (defun View-search-regexp-forward (times regexp)
 383   "Search forward for NTH occurrence of REGEXP in View mode.
 384 Displays line found at center of window.  REGEXP is remembered for
 385 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring."
 386   (interactive "p\nsSearch forward (regexp): ")
 387   (if (> (length regexp) 0)
 388       (progn
 389        ;(view-last-command 'View-search-last-regexp-forward times)
 390         (view-search times regexp))))
 391
 392 (defun View-search-regexp-backward (times regexp)
 393   "Search backward from window start for NTH instance of REGEXP in View mode.
 394 Displays line found at center of window.  REGEXP is remembered for
 395 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring."
 396   (interactive "p\nsSearch backward (regexp): ")
 397   (View-search-regexp-forward (- times) regexp))
 398
 399 (defun View-search-last-regexp-forward (times)
 400   "Search forward from window end for NTH instance of last regexp in View mode.
 401 Displays line found at center of window.  Sets mark at starting position
 402 and pushes mark ring."
 403   (interactive "p")
 404   (View-search-regexp-forward times view-last-regexp))
 405
 406 (defun View-search-last-regexp-backward (times)
 407   "Search backward from window start for NTH instance of last regexp in View mode.
 408 Displays line found at center of window.  Sets mark at starting position and
 409 pushes mark ring."
 410   (interactive "p")
 411   (View-search-regexp-backward times view-last-regexp))
 412
 413 (defun View-back-to-mark (&optional ignore)
 414   "Return to last mark set in View mode, else beginning of file.
 415 Displays line at center of window.  Pops mark ring so successive
 416 invocations return to earlier marks."
 417   (interactive)
 418   (goto-char (or (mark) (point-min)))
 419   (pop-mark)
 420   (recenter (/ (view-window-size) 2)))
 421
 422 (defun view-search (times regexp)
 423   (setq view-last-regexp regexp)
 424   (let (where)
 425     (save-excursion
 426       (move-to-window-line (if (< times 0) 0 -1))
 427       (if (re-search-forward regexp nil t times)
 428           (setq where (point))))
 429     (if where
 430         (progn
 431           (push-mark)
 432           (goto-char where)
 433           (beginning-of-line)
 434           (recenter (/ (view-window-size) 2)))
 435       (message "Can't find occurrence %d of %s" times regexp)
 436       (sit-for 4))))
 437
 438 \f
 439 ;;;###autoload
 440 (define-key ctl-x-map "v" 'view-file)
 441
 442 ;;;###autoload
 443 (define-key ctl-x-4-map "v" 'view-file-other-window)
 444
 445 (provide 'view)
 446
 447 ;;; view.el ends here