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   ;; We used to call suppress-keymap here, but that isn't good in a minor mode.
  75   ;; Self-inserting characters will beep anyway, since the buffer is read-only,
  76   ;; and we should not interfere with letters that serve as useful commands.
  77   (define-key view-mode-map "q" 'view-exit)
  78   (define-key view-mode-map "<" 'beginning-of-buffer)
  79   (define-key view-mode-map ">" 'end-of-buffer)
  80   (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
  81   (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
  82   (define-key view-mode-map " " 'View-scroll-lines-forward)
  83   (define-key view-mode-map "\C-?" 'View-scroll-lines-backward)
  84   (define-key view-mode-map "\n" 'View-scroll-one-more-line)
  85   (define-key view-mode-map "\r" 'View-scroll-one-more-line)
  86   (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
  87   (define-key view-mode-map "g" 'View-goto-line)
  88   (define-key view-mode-map "=" 'what-line)
  89   (define-key view-mode-map "." 'set-mark-command)
  90   (define-key view-mode-map "'" 'View-back-to-mark)
  91   (define-key view-mode-map "@" 'View-back-to-mark)
  92   (define-key view-mode-map "x" 'exchange-point-and-mark)
  93   (define-key view-mode-map "h" 'describe-mode)
  94   (define-key view-mode-map "?" 'describe-mode)
  95   (define-key view-mode-map "s" 'isearch-forward)
  96   (define-key view-mode-map "r" 'isearch-backward)
  97   (define-key view-mode-map "/" 'View-search-regexp-forward)
  98   (define-key view-mode-map "\\" 'View-search-regexp-backward)
  99   ;; This conflicts with the standard binding of isearch-regexp-forward
 100   (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
 101   (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)
 102   (define-key view-mode-map "n" 'View-search-last-regexp-forward)
 103   (define-key view-mode-map "p" 'View-search-last-regexp-backward)
 104   )
 105
 106 (or (assq 'view-mode minor-mode-map-alist)
 107     (setq minor-mode-map-alist
 108           (cons (cons 'view-mode view-mode-map) minor-mode-map-alist)))
 109
 110
 111 ;;;###autoload
 112 (defun view-file (file-name)
 113   "View FILE in View mode, returning to previous buffer when done.
 114 The usual Emacs commands are not available; instead,
 115 a special set of commands (mostly letters and punctuation)
 116 are defined for moving around in the buffer.
 117 Space scrolls forward, Delete scrolls backward.
 118 For list of all View commands, type ? or h while viewing.
 119
 120 This command runs the normal hook `view-mode-hook'."
 121   (interactive "fView file: ")
 122   (let ((old-buf (current-buffer))
 123         (had-a-buf (get-file-buffer file-name))
 124         (buf-to-view (find-file-noselect file-name)))
 125     ;; This used to pass t as second argument,
 126     ;; but then the buffer did not show up in the Buffers menu.
 127     (switch-to-buffer buf-to-view had-a-buf)
 128     (view-mode-enter old-buf
 129                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 130                           'kill-buffer))))
 131
 132 ;;;###autoload
 133 (defun view-file-other-window (file-name)
 134   "View FILE in View mode in other window.
 135 Return to previous buffer when done.
 136 The usual Emacs commands are not available; instead,
 137 a special set of commands (mostly letters and punctuation)
 138 are defined for moving around in the buffer.
 139 Space scrolls forward, Delete scrolls backward.
 140 For list of all View commands, type ? or h while viewing.
 141
 142 This command runs the normal hook `view-mode-hook'."
 143   (interactive "fView file: ")
 144   (let ((old-arrangement (current-window-configuration))
 145         (had-a-buf (get-file-buffer file-name))
 146         (buf-to-view (find-file-noselect file-name)))
 147     (switch-to-buffer-other-window buf-to-view)
 148     (view-mode-enter old-arrangement
 149                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 150                           'kill-buffer))))
 151
 152 ;;;###autoload
 153 (defun view-buffer (buffer-name)
 154   "View BUFFER in View mode, returning to previous buffer when done.
 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 This command runs the normal hook `view-mode-hook'."
 162   (interactive "bView buffer: ")
 163   (let ((old-buf (current-buffer)))
 164     (switch-to-buffer buffer-name t)
 165     (view-mode-enter old-buf nil)))
 166
 167 ;;;###autoload
 168 (defun view-buffer-other-window (buffer-name not-return)
 169   "View BUFFER in View mode in another window.
 170 Return to previous buffer when done, unless NOT-RETURN is non-nil.
 171
 172 The usual Emacs commands are not available in View mode; instead,
 173 a special set of commands (mostly letters and punctuation)
 174 are defined for moving around in the buffer.
 175 Space scrolls forward, Delete scrolls backward.
 176 For list of all View commands, type ? or h while viewing.
 177
 178 This command runs the normal hook `view-mode-hook'."
 179   (interactive "bView buffer:\nP")
 180   (let ((return-to (and not-return (current-window-configuration))))
 181     (switch-to-buffer-other-window buffer-name)
 182     (view-mode-enter return-to)))
 183
 184 ;;;###autoload
 185 (defun view-mode (&optional arg)
 186   "Toggle View mode.
 187 With a prefix argument, turn View mode on if the argument is >= zero
 188 and off if it is not.
 189
 190 If you use this function to turn on View mode, then subsequently
 191 \"exiting\" View mode does nothing except turn View mode off.  The
 192 other way to turn View mode on is by calling `view-mode-enter';
 193 that is what Lisp programs usually use.
 194
 195 Letters do not insert themselves.  Instead these commands are provided.
 196 Most commands take prefix arguments.  Commands dealing with lines
 197 default to \"scroll size\" lines (initially size of window).
 198 Search commands default to a repeat count of one.
 199
 200 M-< or <        move to beginning of buffer.
 201 M-> or >        move to end of buffer.
 202 C-v or Space    scroll forward lines.
 203 M-v or DEL      scroll backward lines.
 204 CR or LF        scroll forward one line (backward with prefix argument).
 205 z               like Space except set number of lines for further
 206                    scrolling commands to scroll by.
 207 C-u and Digits  provide prefix arguments.  `-' denotes negative argument.
 208 =               prints the current line number.
 209 g               goes to line given by prefix argument.
 210 / or M-C-s      searches forward for regular expression
 211 \\ or M-C-r     searches backward for regular expression.
 212 n               searches forward for last regular expression.
 213 p               searches backward for last regular expression.
 214 C-@ or .        set the mark.
 215 x               exchanges point and mark.
 216 C-s or s        do forward incremental search.
 217 C-r or r        do reverse incremental search.
 218 @ or '          return to mark and pops mark ring.
 219                   Mark ring is pushed at start of every
 220                   successful search and when jump to line to occurs.
 221                   The mark is set on jump to buffer start or end.
 222 ? or h          provide help message (list of commands).
 223 \\[help-command]                provides help (list of commands or description of a command).
 224 C-n             moves down lines vertically.
 225 C-p             moves upward lines vertically.
 226 C-l             recenters the screen.
 227 q               exit view-mode and return to previous buffer."
 228   (interactive "P")
 229   (setq view-mode
 230         (if (null arg)
 231             (not view-mode)
 232           (> (prefix-numeric-value arg) 0)))
 233   (force-mode-line-update))
 234
 235 (defun view-mode-enter (&optional prev-buffer action)
 236   "Enter View mode, a Minor mode for viewing text but not editing it.
 237 See the function `view-mode' for more details.
 238
 239 This function runs the normal hook `view-mode-hook'.
 240
 241 \\{view-mode-map}"
 242 ;  Not interactive because dangerous things happen
 243 ;  if you call it without passing a buffer as argument
 244 ;  and they are not easy to fix.
 245 ;  (interactive)
 246   (setq view-old-buffer-read-only buffer-read-only)
 247   (setq view-old-Helper-return-blurb
 248         (and (boundp 'Helper-return-blurb) Helper-return-blurb))
 249
 250   ;; Enable view-exit to make use of the data we just saved
 251   ;; and to perform the exit action.
 252   (setq view-mode-auto-exit t)
 253
 254   (setq buffer-read-only t)
 255   (setq view-mode t)
 256   (setq Helper-return-blurb
 257         (format "continue viewing %s"
 258                 (if (buffer-file-name)
 259                     (file-name-nondirectory (buffer-file-name))
 260                     (buffer-name))))
 261
 262   (setq view-exit-action action)
 263   (setq view-return-here prev-buffer)
 264   (setq view-exit-position (point-marker))
 265
 266   (beginning-of-line)
 267   (setq goal-column nil)
 268
 269   (run-hooks 'view-mode-hook)
 270   (message "%s"
 271      (substitute-command-keys
 272       "Type \\[help-command] for help, \\[describe-mode] for commands, \\[view-exit] to quit.")))
 273 \f
 274 (defun view-exit ()
 275   "Exit from view-mode.
 276 If you viewed an existing buffer, that buffer returns to its previous mode.
 277 If you viewed a file that was not present in Emacs, its buffer is killed."
 278   (interactive)
 279   (setq view-mode nil)
 280   (and view-overlay (delete-overlay view-overlay))
 281   (force-mode-line-update)
 282   (cond (view-mode-auto-exit
 283          (setq buffer-read-only view-old-buffer-read-only)
 284          (setq view-mode-auto-exit nil)
 285
 286          (goto-char view-exit-position)
 287          (set-marker view-exit-position nil)
 288
 289          ;; Now do something to the buffer that we were viewing
 290          ;; (such as kill it).
 291          (let ((viewed-buffer (current-buffer))
 292                (action view-exit-action))
 293            (cond
 294             ((bufferp view-return-here)
 295              (switch-to-buffer view-return-here))
 296             ((window-configuration-p view-return-here)
 297              (set-window-configuration view-return-here)))
 298            (if action (funcall action viewed-buffer))))))
 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-mode-hook nil
 306   "Normal hook run when starting to view a buffer or file.")
 307
 308 ;(defun view-last-command (&optional who what)
 309 ;  (setq view-last-command-entry this-command)
 310 ;  (setq view-last-command who)
 311 ;  (setq view-last-command-argument what))
 312
 313 ;(defun View-repeat-last-command ()
 314 ;  "Repeat last command issued in View mode."
 315 ;  (interactive)
 316 ;  (if (and view-last-command
 317 ;          (eq view-last-command-entry last-command))
 318 ;      (funcall view-last-command view-last-command-argument))
 319 ;  (setq this-command view-last-command-entry))
 320
 321 (defun View-goto-line (line)
 322   "Move to line LINE in View mode.
 323 Display is centered at LINE.  Sets mark at starting position and pushes
 324 mark ring."
 325   (interactive "p")
 326   (push-mark)
 327   (goto-line line)
 328   (recenter (/ (view-window-size) 2)))
 329
 330 (defun View-scroll-lines-forward (&optional lines)
 331   "Scroll forward in View mode, or exit if end of text is visible.
 332 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 333 Arg is number of lines to scroll."
 334   (interactive "P")
 335   (setq lines
 336         (if lines (prefix-numeric-value lines)
 337           (view-scroll-size)))
 338   (if (and (pos-visible-in-window-p (point-max))
 339            ;; Allow scrolling backward at the end of the buffer.
 340            (> lines 0)
 341            view-mode-auto-exit)
 342       (view-exit)
 343     ;; (view-last-command 'View-scroll-lines-forward lines)
 344     (if (>= lines (view-window-size))
 345         (scroll-up nil)
 346       (if (>= (- lines) (view-window-size))
 347           (scroll-down nil)
 348         (scroll-up lines)))
 349     (cond ((pos-visible-in-window-p (point-max))
 350            (goto-char (point-max))
 351            (message "%s"
 352                     (substitute-command-keys
 353                      "End.  Type \\[view-exit] to quit viewing."))))
 354     (move-to-window-line -1)
 355     (beginning-of-line)))
 356
 357 (defun View-scroll-lines-forward-set-scroll-size (&optional lines)
 358   "Scroll forward LINES lines in View mode, setting the \"scroll size\".
 359 This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
 360 The absolute value of LINES is used, so this command can be used to scroll
 361 backwards (but \"scroll size\" is always positive).  If LINES is greater than
 362 window height or omitted, then window height is assumed.  If LINES is less
 363 than window height then scrolling context is provided from previous screen."
 364   (interactive "P")
 365   (if (not lines)
 366       (setq view-scroll-size (view-window-size))
 367     (setq lines (prefix-numeric-value lines))
 368     (setq view-scroll-size
 369           (min (if (> lines 0) lines (- lines)) (view-window-size))))
 370   (View-scroll-lines-forward lines))
 371
 372 (defun View-scroll-one-more-line (&optional arg)
 373   "Scroll one more line up in View mode.
 374 With ARG scroll one line down."
 375   (interactive "P")
 376   (View-scroll-lines-forward (if (not arg) 1 -1)))
 377
 378 (defun View-scroll-lines-backward (&optional lines)
 379   "Scroll backward in View mode.
 380 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 381 Arg is number of lines to scroll."
 382   (interactive "P")
 383   (View-scroll-lines-forward (if lines
 384                                  (- (prefix-numeric-value lines))
 385                                (- (view-scroll-size)))))
 386
 387 (defun View-search-regexp-forward (n regexp)
 388   "Search forward for Nth occurrence of REGEXP.
 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
 392 The variable `view-highlight-face' controls the face that is used
 393 for highlighting the match that is found."
 394   (interactive "p\nsSearch forward (regexp): ")
 395 ;;;(view-last-command 'View-search-last-regexp-forward n)
 396   (view-search n (if (equal regexp "") view-last-regexp regexp)))
 397
 398 (defun View-search-regexp-backward (n regexp)
 399   "Search backward from window start for Nth instance of REGEXP.
 400 Displays line found at center of window.  REGEXP is remembered for
 401 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
 402
 403 The variable `view-highlight-face' controls the face that is used
 404 for highlighting the match that is found."
 405   (interactive "p\nsSearch backward (regexp): ")
 406   (View-search-regexp-forward (- n)
 407                               (if (equal regexp "") view-last-regexp regexp)))
 408
 409 (defun View-search-last-regexp-forward (n)
 410   "Search forward from window end for Nth instance of last regexp.
 411 Displays line found at center of window.  Sets mark at starting position
 412 and pushes mark ring.
 413
 414 The variable `view-highlight-face' controls the face that is used
 415 for highlighting the match that is found."
 416   (interactive "p")
 417   (if view-last-regexp
 418       (View-search-regexp-forward n view-last-regexp)
 419     (error "No previous View-mode search")))
 420
 421 (defun View-search-last-regexp-backward (n)
 422   "Search backward from window start for Nth instance of last regexp.
 423 Displays line found at center of window.  Sets mark at starting position and
 424 pushes mark ring.
 425
 426 The variable `view-highlight-face' controls the face that is used
 427 for highlighting the match that is found."
 428   (interactive "p")
 429   (if view-last-regexp
 430       (View-search-regexp-backward n view-last-regexp)
 431     (error "No previous View-mode search")))
 432
 433 (defun View-back-to-mark (&optional ignore)
 434   "Return to last mark set in View mode, else beginning of file.
 435 Displays line at center of window.  Pops mark ring so successive
 436 invocations return to earlier marks."
 437   (interactive)
 438   (goto-char (or (mark t) (point-min)))
 439   (pop-mark)
 440   (recenter (/ (view-window-size) 2)))
 441
 442 (defun view-search (times regexp)
 443   (setq view-last-regexp regexp)
 444   (let (where)
 445     (save-excursion
 446       (move-to-window-line (if (< times 0) 0 -1))
 447       (if (re-search-forward regexp nil t times)
 448           (setq where (point))))
 449     (if where
 450         (progn
 451           (push-mark)
 452           (goto-char where)
 453           (if view-overlay
 454               (move-overlay view-overlay (match-beginning 0) (match-end 0))
 455             (setq view-overlay
 456                   (make-overlay (match-beginning 0) (match-end 0))))
 457           (overlay-put view-overlay 'face view-highlight-face)
 458           (beginning-of-line)
 459           (recenter (/ (view-window-size) 2)))
 460       (message "Can't find occurrence %d of %s" times regexp)
 461       (sit-for 4))))
 462
 463 \f
 464 (provide 'view)
 465
 466 ;;; view.el ends here