lisp/view.el

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