lisp/view.el

   1 ;;; view.el --- peruse file or buffer without editing.
   2
   3 ;; Copyright (C) 1985, 1989, 1994, 1995 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 the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; This package provides the `view' minor mode documented in the Emacs
  28 ;; user's manual.
  29
  30 ;;; Code:
  31
  32 ;;;###autoload
  33 (defvar view-highlight-face 'highlight
  34    "*The overlay face used for highlighting the match found by View mode search.")
  35
  36 (defvar view-mode nil "Non-nil if View mode is enabled.")
  37 (make-variable-buffer-local 'view-mode)
  38
  39 (defvar view-mode-auto-exit nil
  40   "Non-nil means scrolling past the end of buffer exits View mode.")
  41 (make-variable-buffer-local 'view-mode-auto-exit)
  42
  43 (defvar view-old-buffer-read-only nil)
  44 (make-variable-buffer-local 'view-old-buffer-read-only)
  45 (defvar view-old-Helper-return-blurb)
  46 (make-variable-buffer-local 'view-old-Helper-return-blurb)
  47
  48 (defvar view-scroll-size nil)
  49 (make-variable-buffer-local 'view-scroll-size)
  50
  51 (defvar view-last-regexp nil)
  52 (make-variable-buffer-local 'view-last-regexp)
  53
  54 (defvar view-exit-action nil)
  55 (make-variable-buffer-local 'view-exit-action)
  56 (defvar view-return-here nil)
  57 (make-variable-buffer-local 'view-return-here)
  58 (defvar view-exit-position nil)
  59 (make-variable-buffer-local 'view-exit-position)
  60
  61 (defvar view-overlay nil
  62   "Overlay used to display where a search operation found its match.
  63 This is local in each buffer, once it is used.")
  64 (make-variable-buffer-local 'view-overlay)
  65
  66 (or (assq 'view-mode minor-mode-alist)
  67     (setq minor-mode-alist
  68           (cons '(view-mode " View") minor-mode-alist)))
  69
  70 (defvar view-mode-map nil)
  71 (if view-mode-map
  72     nil
  73   (setq view-mode-map (make-keymap))
  74   (suppress-keymap view-mode-map)
  75   (define-key view-mode-map "q" 'view-exit)
  76   (define-key view-mode-map "<" 'beginning-of-buffer)
  77   (define-key view-mode-map ">" 'end-of-buffer)
  78   (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
  79   (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
  80   (define-key view-mode-map " " 'View-scroll-lines-forward)
  81   (define-key view-mode-map "\C-?" 'View-scroll-lines-backward)
  82   (define-key view-mode-map "\n" 'View-scroll-one-more-line)
  83   (define-key view-mode-map "\r" 'View-scroll-one-more-line)
  84   (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
  85   (define-key view-mode-map "g" 'View-goto-line)
  86   (define-key view-mode-map "=" 'what-line)
  87   (define-key view-mode-map "." 'set-mark-command)
  88   (define-key view-mode-map "'" 'View-back-to-mark)
  89   (define-key view-mode-map "@" 'View-back-to-mark)
  90   (define-key view-mode-map "x" 'exchange-point-and-mark)
  91   (define-key view-mode-map "h" 'describe-mode)
  92   (define-key view-mode-map "?" 'describe-mode)
  93   (define-key view-mode-map "s" 'isearch-forward)
  94   (define-key view-mode-map "r" 'isearch-backward)
  95   (define-key view-mode-map "/" 'View-search-regexp-forward)
  96   (define-key view-mode-map "\\" 'View-search-regexp-backward)
  97   ;; This conflicts with the standard binding of isearch-regexp-forward
  98   (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
  99   (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)
 100   (define-key view-mode-map "n" 'View-search-last-regexp-forward)
 101   (define-key view-mode-map "p" 'View-search-last-regexp-backward)
 102   )
 103
 104 (or (assq 'view-mode minor-mode-map-alist)
 105     (setq minor-mode-map-alist
 106           (cons (cons 'view-mode view-mode-map) minor-mode-map-alist)))
 107
 108
 109 ;;;###autoload
 110 (defun view-file (file-name)
 111   "View FILE in View mode, returning to previous buffer when done.
 112 The usual Emacs commands are not available; instead,
 113 a special set of commands (mostly letters and punctuation)
 114 are defined for moving around in the buffer.
 115 Space scrolls forward, Delete scrolls backward.
 116 For list of all View commands, type ? or h while viewing.
 117
 118 This command runs the normal hook `view-mode-hook'."
 119   (interactive "fView file: ")
 120   (let ((old-buf (current-buffer))
 121         (had-a-buf (get-file-buffer file-name))
 122         (buf-to-view (find-file-noselect file-name)))
 123     ;; This used to pass t as second argument,
 124     ;; but then the buffer did not show up in the Buffers menu.
 125     (switch-to-buffer buf-to-view had-a-buf)
 126     (view-mode-enter old-buf
 127                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 128                           'kill-buffer))))
 129
 130 ;;;###autoload
 131 (defun view-file-other-window (file-name)
 132   "View FILE in View mode in other window.
 133 Return 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 This command runs the normal hook `view-mode-hook'."
 141   (interactive "fView file: ")
 142   (let ((old-arrangement (current-window-configuration))
 143         (had-a-buf (get-file-buffer file-name))
 144         (buf-to-view (find-file-noselect file-name)))
 145     (switch-to-buffer-other-window buf-to-view)
 146     (view-mode-enter old-arrangement
 147                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 148                           'kill-buffer))))
 149
 150 ;;;###autoload
 151 (defun view-buffer (buffer-name)
 152   "View BUFFER in View mode, returning to previous buffer when done.
 153 The usual Emacs commands are not available; instead,
 154 a special set of commands (mostly letters and punctuation)
 155 are defined for moving around in the buffer.
 156 Space scrolls forward, Delete scrolls backward.
 157 For list of all View commands, type ? or h while viewing.
 158
 159 This command runs the normal hook `view-mode-hook'."
 160   (interactive "bView buffer: ")
 161   (let ((old-buf (current-buffer)))
 162     (switch-to-buffer buffer-name t)
 163     (view-mode-enter old-buf nil)))
 164
 165 ;;;###autoload
 166 (defun view-buffer-other-window (buffer-name not-return)
 167   "View BUFFER in View mode in another window.
 168 Return to previous buffer when done, unless NOT-RETURN is non-nil.
 169
 170 The usual Emacs commands are not available in View mode; instead,
 171 a special set of commands (mostly letters and punctuation)
 172 are defined for moving around in the buffer.
 173 Space scrolls forward, Delete scrolls backward.
 174 For list of all View commands, type ? or h while viewing.
 175
 176 This command runs the normal hook `view-mode-hook'."
 177   (interactive "bView buffer:\nP")
 178   (let ((return-to (and not-return (current-window-configuration))))
 179     (switch-to-buffer-other-window buffer-name)
 180     (view-mode-enter return-to)))
 181
 182 ;;;###autoload
 183 (defun view-mode (&optional arg)
 184   "Toggle View mode.
 185 If you use this function to turn on View mode,
 186 \"exiting\" View mode does nothing except turn View mode off.
 187 The other way to turn View mode on is by calling
 188 `view-mode-enter'.
 189
 190 Letters do not insert themselves.  Instead these commands are provided.
 191 Most commands take prefix arguments.  Commands dealing with lines
 192 default to \"scroll size\" lines (initially size of window).
 193 Search commands default to a repeat count of one.
 194
 195 M-< or <        move to beginning of buffer.
 196 M-> or >        move to end of buffer.
 197 C-v or Space    scroll forward lines.
 198 M-v or DEL      scroll backward lines.
 199 CR or LF        scroll forward one line (backward with prefix argument).
 200 z               like Space except set number of lines for further
 201                    scrolling commands to scroll by.
 202 C-u and Digits  provide prefix arguments.  `-' denotes negative argument.
 203 =               prints the current line number.
 204 g               goes to line given by prefix argument.
 205 / or M-C-s      searches forward for regular expression
 206 \\ or M-C-r     searches backward for regular expression.
 207 n               searches forward for last regular expression.
 208 p               searches backward for last regular expression.
 209 C-@ or .        set the mark.
 210 x               exchanges point and mark.
 211 C-s or s        do forward incremental search.
 212 C-r or r        do reverse incremental search.
 213 @ or '          return to mark and pops mark ring.
 214                   Mark ring is pushed at start of every
 215                   successful search and when jump to line to occurs.
 216                   The mark is set on jump to buffer start or end.
 217 ? or h          provide help message (list of commands).
 218 \\[help-command]                provides help (list of commands or description of a command).
 219 C-n             moves down lines vertically.
 220 C-p             moves upward lines vertically.
 221 C-l             recenters the screen.
 222 q               exit view-mode and return to previous buffer."
 223   (interactive "P")
 224   (setq view-mode
 225         (if (null arg)
 226             (not view-mode)
 227           (> (prefix-numeric-value arg) 0)))
 228   (force-mode-line-update))
 229
 230 (defun view-mode-enter (&optional prev-buffer action)
 231   "Enter View mode, a Minor mode for viewing text but not editing it.
 232 See the function `view-mode' for more details.
 233
 234 This function runs the normal hook `view-mode-hook'.
 235
 236 \\{view-mode-map}"
 237 ;  Not interactive because dangerous things happen
 238 ;  if you call it without passing a buffer as argument
 239 ;  and they are not easy to fix.
 240 ;  (interactive)
 241   (setq view-old-buffer-read-only buffer-read-only)
 242   (setq view-old-Helper-return-blurb
 243         (and (boundp 'Helper-return-blurb) Helper-return-blurb))
 244
 245   ;; Enable view-exit to make use of the data we just saved
 246   ;; and to perform the exit action.
 247   (setq view-mode-auto-exit t)
 248
 249   (setq buffer-read-only t)
 250   (setq view-mode t)
 251   (setq Helper-return-blurb
 252         (format "continue viewing %s"
 253                 (if (buffer-file-name)
 254                     (file-name-nondirectory (buffer-file-name))
 255                     (buffer-name))))
 256
 257   (setq view-exit-action action)
 258   (setq view-return-here prev-buffer)
 259   (setq view-exit-position (point-marker))
 260
 261   (beginning-of-line)
 262   (setq goal-column nil)
 263
 264   (run-hooks 'view-mode-hook)
 265   (message
 266      (substitute-command-keys
 267       "Type \\[help-command] for help, \\[describe-mode] for commands, \\[view-exit] to quit.")))
 268 \f
 269 (defun view-exit ()
 270   "Exit from view-mode.
 271 If you viewed an existing buffer, that buffer returns to its previous mode.
 272 If you viewed a file that was not present in Emacs, its buffer is killed."
 273   (interactive)
 274   (setq view-mode nil)
 275   (and view-overlay (delete-overlay view-overlay))
 276   (force-mode-line-update)
 277   (cond (view-mode-auto-exit
 278          (setq buffer-read-only view-old-buffer-read-only)
 279          (setq view-mode-auto-exit nil)
 280
 281          (goto-char view-exit-position)
 282          (set-marker view-exit-position nil)
 283
 284          ;; Now do something to the buffer that we were viewing
 285          ;; (such as kill it).
 286          (let ((viewed-buffer (current-buffer))
 287                (action view-exit-action))
 288            (cond
 289             ((bufferp view-return-here)
 290              (switch-to-buffer view-return-here))
 291             ((window-configuration-p view-return-here)
 292              (set-window-configuration view-return-here)))
 293            (if action (funcall action viewed-buffer))))))
 294
 295 (defun view-window-size () (1- (window-height)))
 296
 297 (defun view-scroll-size ()
 298   (min (view-window-size) (or view-scroll-size (view-window-size))))
 299
 300 (defvar view-mode-hook nil
 301   "Normal hook run when starting to view a buffer or file.")
 302
 303 ;(defun view-last-command (&optional who what)
 304 ;  (setq view-last-command-entry this-command)
 305 ;  (setq view-last-command who)
 306 ;  (setq view-last-command-argument what))
 307
 308 ;(defun View-repeat-last-command ()
 309 ;  "Repeat last command issued in View mode."
 310 ;  (interactive)
 311 ;  (if (and view-last-command
 312 ;          (eq view-last-command-entry last-command))
 313 ;      (funcall view-last-command view-last-command-argument))
 314 ;  (setq this-command view-last-command-entry))
 315
 316 (defun View-goto-line (line)
 317   "Move to line LINE in View mode.
 318 Display is centered at LINE.  Sets mark at starting position and pushes
 319 mark ring."
 320   (interactive "p")
 321   (push-mark)
 322   (goto-line line)
 323   (recenter (/ (view-window-size) 2)))
 324
 325 (defun View-scroll-lines-forward (&optional lines)
 326   "Scroll forward in View mode, or exit if end of text is visible.
 327 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 328 Arg is number of lines to scroll."
 329   (interactive "P")
 330   (setq lines
 331         (if lines (prefix-numeric-value lines)
 332           (view-scroll-size)))
 333   (if (and (pos-visible-in-window-p (point-max))
 334            ;; Allow scrolling backward at the end of the buffer.
 335            (> lines 0)
 336            view-mode-auto-exit)
 337       (view-exit)
 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            (message (substitute-command-keys
 347                      "End.  Type \\[view-exit] to quit viewing."))))
 348     (move-to-window-line -1)
 349     (beginning-of-line)))
 350
 351 (defun View-scroll-lines-forward-set-scroll-size (&optional lines)
 352   "Scroll forward LINES lines in View mode, setting the \"scroll size\".
 353 This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
 354 The absolute value of LINES is used, so this command can be used to scroll
 355 backwards (but \"scroll size\" is always positive).  If LINES is greater than
 356 window height or omitted, then window height is assumed.  If LINES is less
 357 than window height then scrolling context is provided from previous screen."
 358   (interactive "P")
 359   (if (not lines)
 360       (setq view-scroll-size (view-window-size))
 361     (setq lines (prefix-numeric-value lines))
 362     (setq view-scroll-size
 363           (min (if (> lines 0) lines (- lines)) (view-window-size))))
 364   (View-scroll-lines-forward lines))
 365
 366 (defun View-scroll-one-more-line (&optional arg)
 367   "Scroll one more line up in View mode.
 368 With ARG scroll one line down."
 369   (interactive "P")
 370   (View-scroll-lines-forward (if (not arg) 1 -1)))
 371
 372 (defun View-scroll-lines-backward (&optional lines)
 373   "Scroll backward in View mode.
 374 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 375 Arg is number of lines to scroll."
 376   (interactive "P")
 377   (View-scroll-lines-forward (if lines
 378                                  (- (prefix-numeric-value lines))
 379                                (- (view-scroll-size)))))
 380
 381 (defun View-search-regexp-forward (n regexp)
 382   "Search forward for Nth occurrence of REGEXP.
 383 Displays line found at center of window.  REGEXP is remembered for
 384 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
 385
 386 The variable `view-highlight-face' controls the face that is used
 387 for highlighting the match that is found."
 388   (interactive "p\nsSearch forward (regexp): ")
 389 ;;;(view-last-command 'View-search-last-regexp-forward n)
 390   (view-search n (if (equal regexp "") view-last-regexp regexp)))
 391
 392 (defun View-search-regexp-backward (n regexp)
 393   "Search backward from window start for Nth instance of REGEXP.
 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
 397 The variable `view-highlight-face' controls the face that is used
 398 for highlighting the match that is found."
 399   (interactive "p\nsSearch backward (regexp): ")
 400   (View-search-regexp-forward (- n)
 401                               (if (equal regexp "") view-last-regexp regexp)))
 402
 403 (defun View-search-last-regexp-forward (n)
 404   "Search forward from window end for Nth instance of last regexp.
 405 Displays line found at center of window.  Sets mark at starting position
 406 and pushes mark ring.
 407
 408 The variable `view-highlight-face' controls the face that is used
 409 for highlighting the match that is found."
 410   (interactive "p")
 411   (View-search-regexp-forward n view-last-regexp))
 412
 413 (defun View-search-last-regexp-backward (n)
 414   "Search backward from window start for Nth instance of last regexp.
 415 Displays line found at center of window.  Sets mark at starting position and
 416 pushes mark ring.
 417
 418 The variable `view-highlight-face' controls the face that is used
 419 for highlighting the match that is found."
 420   (interactive "p")
 421   (View-search-regexp-backward n view-last-regexp))
 422
 423 (defun View-back-to-mark (&optional ignore)
 424   "Return to last mark set in View mode, else beginning of file.
 425 Displays line at center of window.  Pops mark ring so successive
 426 invocations return to earlier marks."
 427   (interactive)
 428   (goto-char (or (mark t) (point-min)))
 429   (pop-mark)
 430   (recenter (/ (view-window-size) 2)))
 431
 432 (defun view-search (times regexp)
 433   (setq view-last-regexp regexp)
 434   (let (where)
 435     (save-excursion
 436       (move-to-window-line (if (< times 0) 0 -1))
 437       (if (re-search-forward regexp nil t times)
 438           (setq where (point))))
 439     (if where
 440         (progn
 441           (push-mark)
 442           (goto-char where)
 443           (if view-overlay
 444               (move-overlay view-overlay (match-beginning 0) (match-end 0))
 445             (setq view-overlay
 446                   (make-overlay (match-beginning 0) (match-end 0))))
 447           (overlay-put view-overlay 'face view-highlight-face)
 448           (beginning-of-line)
 449           (recenter (/ (view-window-size) 2)))
 450       (message "Can't find occurrence %d of %s" times regexp)
 451       (sit-for 4))))
 452
 453 \f
 454 (provide 'view)
 455
 456 ;;; view.el ends here