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