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 Some commands, such as \\[view-file], set this to t locally;
  42 the only way to override that is to set it to nil using `view-mode-hook'.")
  43
  44 (make-variable-buffer-local 'view-mode-auto-exit)
  45
  46 (defvar view-old-buffer-read-only nil)
  47 (make-variable-buffer-local 'view-old-buffer-read-only)
  48 (defvar view-old-Helper-return-blurb)
  49 (make-variable-buffer-local 'view-old-Helper-return-blurb)
  50
  51 (defvar view-scroll-size nil)
  52 (make-variable-buffer-local 'view-scroll-size)
  53
  54 (defvar view-last-regexp nil)
  55 (make-variable-buffer-local 'view-last-regexp)
  56
  57 (defvar view-exit-action nil)
  58 (make-variable-buffer-local 'view-exit-action)
  59 (defvar view-return-here nil)
  60 (make-variable-buffer-local 'view-return-here)
  61 (defvar view-exit-position nil)
  62 (make-variable-buffer-local 'view-exit-position)
  63
  64 (defvar view-overlay nil
  65   "Overlay used to display where a search operation found its match.
  66 This is local in each buffer, once it is used.")
  67 (make-variable-buffer-local 'view-overlay)
  68
  69 (or (assq 'view-mode minor-mode-alist)
  70     (setq minor-mode-alist
  71           (cons '(view-mode " View") minor-mode-alist)))
  72
  73 (defvar view-mode-map nil)
  74 (if view-mode-map
  75     nil
  76   (setq view-mode-map (make-keymap))
  77   ;; We used to call suppress-keymap here, but that isn't good in a minor mode.
  78   ;; Self-inserting characters will beep anyway, since the buffer is read-only,
  79   ;; and we should not interfere with letters that serve as useful commands.
  80   (define-key view-mode-map "q" 'view-exit)
  81   (define-key view-mode-map "<" 'beginning-of-buffer)
  82   (define-key view-mode-map ">" 'end-of-buffer)
  83   (define-key view-mode-map "\ev" 'View-scroll-lines-backward)
  84   (define-key view-mode-map "\C-v" 'View-scroll-lines-forward)
  85   (define-key view-mode-map " " 'View-scroll-lines-forward)
  86   (define-key view-mode-map "\C-?" 'View-scroll-lines-backward)
  87   (define-key view-mode-map "\n" 'View-scroll-one-more-line)
  88   (define-key view-mode-map "\r" 'View-scroll-one-more-line)
  89   (define-key view-mode-map "z" 'View-scroll-lines-forward-set-scroll-size)
  90   (define-key view-mode-map "g" 'View-goto-line)
  91   (define-key view-mode-map "=" 'what-line)
  92   (define-key view-mode-map "." 'set-mark-command)
  93   (define-key view-mode-map "'" 'View-back-to-mark)
  94   (define-key view-mode-map "@" 'View-back-to-mark)
  95   (define-key view-mode-map "x" 'exchange-point-and-mark)
  96   (define-key view-mode-map "h" 'describe-mode)
  97   (define-key view-mode-map "?" 'describe-mode)
  98   (define-key view-mode-map "s" 'isearch-forward)
  99   (define-key view-mode-map "r" 'isearch-backward)
 100   (define-key view-mode-map "/" 'View-search-regexp-forward)
 101   (define-key view-mode-map "\\" 'View-search-regexp-backward)
 102   ;; This conflicts with the standard binding of isearch-regexp-forward
 103   (define-key view-mode-map "\e\C-s" 'View-search-regexp-forward)
 104   (define-key view-mode-map "\e\C-r" 'View-search-regexp-backward)
 105   (define-key view-mode-map "n" 'View-search-last-regexp-forward)
 106   (define-key view-mode-map "p" 'View-search-last-regexp-backward)
 107   )
 108
 109 (or (assq 'view-mode minor-mode-map-alist)
 110     (setq minor-mode-map-alist
 111           (cons (cons 'view-mode view-mode-map) minor-mode-map-alist)))
 112
 113
 114 ;;;###autoload
 115 (defun view-file (file-name)
 116   "View FILE in View mode, returning to previous buffer when done.
 117 The usual Emacs commands are not available; instead,
 118 a special set of commands (mostly letters and punctuation)
 119 are defined for moving around in the buffer.
 120 Space scrolls forward, Delete scrolls backward.
 121 For list of all View commands, type ? or h while viewing.
 122
 123 This command runs the normal hook `view-mode-hook'."
 124   (interactive "fView file: ")
 125   (let ((old-buf (current-buffer))
 126         (had-a-buf (get-file-buffer file-name))
 127         (buf-to-view (find-file-noselect file-name)))
 128     ;; This used to pass t as second argument,
 129     ;; but then the buffer did not show up in the Buffers menu.
 130     (switch-to-buffer buf-to-view had-a-buf)
 131     (view-mode-enter old-buf
 132                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 133                           'kill-buffer))))
 134
 135 ;;;###autoload
 136 (defun view-file-other-window (file-name)
 137   "View FILE in View mode in other window.
 138 Return to previous buffer when done.
 139 The usual Emacs commands are not available; instead,
 140 a special set of commands (mostly letters and punctuation)
 141 are defined for moving around in the buffer.
 142 Space scrolls forward, Delete scrolls backward.
 143 For list of all View commands, type ? or h while viewing.
 144
 145 This command runs the normal hook `view-mode-hook'."
 146   (interactive "fView file: ")
 147   (let ((old-arrangement (current-window-configuration))
 148         (had-a-buf (get-file-buffer file-name))
 149         (buf-to-view (find-file-noselect file-name)))
 150     (switch-to-buffer-other-window buf-to-view)
 151     (view-mode-enter old-arrangement
 152                      (and (not had-a-buf) (not (buffer-modified-p buf-to-view))
 153                           'kill-buffer))))
 154
 155 ;;;###autoload
 156 (defun view-buffer (buffer-name)
 157   "View BUFFER in View mode, returning to previous buffer when done.
 158 The usual Emacs commands are not available; instead,
 159 a special set of commands (mostly letters and punctuation)
 160 are defined for moving around in the buffer.
 161 Space scrolls forward, Delete scrolls backward.
 162 For list of all View commands, type ? or h while viewing.
 163
 164 This command runs the normal hook `view-mode-hook'."
 165   (interactive "bView buffer: ")
 166   (let ((old-buf (current-buffer)))
 167     (switch-to-buffer buffer-name t)
 168     (view-mode-enter old-buf nil)))
 169
 170 ;;;###autoload
 171 (defun view-buffer-other-window (buffer-name not-return)
 172   "View BUFFER in View mode in another window.
 173 Return to previous buffer when done, unless NOT-RETURN is non-nil.
 174
 175 The usual Emacs commands are not available in View mode; instead,
 176 a special set of commands (mostly letters and punctuation)
 177 are defined for moving around in the buffer.
 178 Space scrolls forward, Delete scrolls backward.
 179 For list of all View commands, type ? or h while viewing.
 180
 181 This command runs the normal hook `view-mode-hook'."
 182   (interactive "bView buffer:\nP")
 183   (let ((return-to (and not-return (current-window-configuration))))
 184     (switch-to-buffer-other-window buffer-name)
 185     (view-mode-enter return-to)))
 186
 187 ;;;###autoload
 188 (defun view-mode (&optional arg)
 189   "Toggle View mode.
 190 With a prefix argument, turn View mode on if the argument is >= zero
 191 and off if it is not.
 192
 193 If you use this function to turn on View mode, then subsequently
 194 \"exiting\" View mode does nothing except turn View mode off.  The
 195 other way to turn View mode on is by calling `view-mode-enter';
 196 that is what Lisp programs usually use.
 197
 198 Letters do not insert themselves.  Instead these commands are provided.
 199 Most commands take prefix arguments.  Commands dealing with lines
 200 default to \"scroll size\" lines (initially size of window).
 201 Search commands default to a repeat count of one.
 202
 203 M-< or <        move to beginning of buffer.
 204 M-> or >        move to end of buffer.
 205 C-v or Space    scroll forward lines.
 206 M-v or DEL      scroll backward lines.
 207 CR or LF        scroll forward one line (backward with prefix argument).
 208 z               like Space except set number of lines for further
 209                    scrolling commands to scroll by.
 210 C-u and Digits  provide prefix arguments.  `-' denotes negative argument.
 211 =               prints the current line number.
 212 g               goes to line given by prefix argument.
 213 / or M-C-s      searches forward for regular expression
 214 \\ or M-C-r     searches backward for regular expression.
 215 n               searches forward for last regular expression.
 216 p               searches backward for last regular expression.
 217 C-@ or .        set the mark.
 218 x               exchanges point and mark.
 219 C-s or s        do forward incremental search.
 220 C-r or r        do reverse incremental search.
 221 @ or '          return to mark and pops mark ring.
 222                   Mark ring is pushed at start of every
 223                   successful search and when jump to line to occurs.
 224                   The mark is set on jump to buffer start or end.
 225 ? or h          provide help message (list of commands).
 226 \\[help-command]                provides help (list of commands or description of a command).
 227 C-n             moves down lines vertically.
 228 C-p             moves upward lines vertically.
 229 C-l             recenters the screen.
 230 q               exit view-mode and return to previous buffer."
 231   (interactive "P")
 232   (setq view-mode
 233         (if (null arg)
 234             (not view-mode)
 235           (> (prefix-numeric-value arg) 0)))
 236   (force-mode-line-update))
 237
 238 (defun view-mode-enter (&optional prev-buffer action)
 239   "Enter View mode, a Minor mode for viewing text but not editing it.
 240 See the function `view-mode' for more details.
 241
 242 This function runs the normal hook `view-mode-hook'.
 243
 244 \\{view-mode-map}"
 245 ;  Not interactive because dangerous things happen
 246 ;  if you call it without passing a buffer as argument
 247 ;  and they are not easy to fix.
 248 ;  (interactive)
 249   (setq view-old-buffer-read-only buffer-read-only)
 250   (setq view-old-Helper-return-blurb
 251         (and (boundp 'Helper-return-blurb) Helper-return-blurb))
 252
 253   ;; Enable view-exit to make use of the data we just saved
 254   ;; and to perform the exit action.
 255   (setq view-mode-auto-exit t)
 256
 257   (setq buffer-read-only t)
 258   (setq view-mode t)
 259   (setq Helper-return-blurb
 260         (format "continue viewing %s"
 261                 (if (buffer-file-name)
 262                     (file-name-nondirectory (buffer-file-name))
 263                     (buffer-name))))
 264
 265   (setq view-exit-action action)
 266   (setq view-return-here prev-buffer)
 267   (setq view-exit-position (point-marker))
 268
 269   (beginning-of-line)
 270   (setq goal-column nil)
 271
 272   (run-hooks 'view-mode-hook)
 273   (message "%s"
 274      (substitute-command-keys
 275       "Type \\[help-command] for help, \\[describe-mode] for commands, \\[view-exit] to quit.")))
 276 \f
 277 (defun view-exit ()
 278   "Exit from view-mode.
 279 If you viewed an existing buffer, that buffer returns to its previous mode.
 280 If you viewed a file that was not present in Emacs, its buffer is killed."
 281   (interactive)
 282   (setq view-mode nil)
 283   (and view-overlay (delete-overlay view-overlay))
 284   (force-mode-line-update)
 285   (cond (view-mode-auto-exit
 286          (setq buffer-read-only view-old-buffer-read-only)
 287          (setq view-mode-auto-exit nil)
 288
 289          (goto-char view-exit-position)
 290          (set-marker view-exit-position nil)
 291
 292          ;; Now do something to the buffer that we were viewing
 293          ;; (such as kill it).
 294          (let ((viewed-buffer (current-buffer))
 295                (action view-exit-action))
 296            (cond
 297             ((bufferp view-return-here)
 298              (switch-to-buffer view-return-here))
 299             ((window-configuration-p view-return-here)
 300              (set-window-configuration view-return-here)))
 301            (if action (funcall action viewed-buffer))))))
 302
 303 (defun view-window-size () (1- (window-height)))
 304
 305 (defun view-scroll-size ()
 306   (min (view-window-size) (or view-scroll-size (view-window-size))))
 307
 308 (defvar view-mode-hook nil
 309   "Normal hook run when starting to view a buffer or file.")
 310
 311 ;(defun view-last-command (&optional who what)
 312 ;  (setq view-last-command-entry this-command)
 313 ;  (setq view-last-command who)
 314 ;  (setq view-last-command-argument what))
 315
 316 ;(defun View-repeat-last-command ()
 317 ;  "Repeat last command issued in View mode."
 318 ;  (interactive)
 319 ;  (if (and view-last-command
 320 ;          (eq view-last-command-entry last-command))
 321 ;      (funcall view-last-command view-last-command-argument))
 322 ;  (setq this-command view-last-command-entry))
 323
 324 (defun View-goto-line (line)
 325   "Move to line LINE in View mode.
 326 Display is centered at LINE.  Sets mark at starting position and pushes
 327 mark ring."
 328   (interactive "p")
 329   (push-mark)
 330   (goto-line line)
 331   (recenter (/ (view-window-size) 2)))
 332
 333 (defun View-scroll-lines-forward (&optional lines)
 334   "Scroll forward in View mode, or exit if end of text is visible.
 335 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 336 Arg is number of lines to scroll."
 337   (interactive "P")
 338   (setq lines
 339         (if lines (prefix-numeric-value lines)
 340           (view-scroll-size)))
 341   (if (and (pos-visible-in-window-p (point-max))
 342            ;; Allow scrolling backward at the end of the buffer.
 343            (> lines 0)
 344            view-mode-auto-exit)
 345       (view-exit)
 346     ;; (view-last-command 'View-scroll-lines-forward lines)
 347     (if (>= lines (view-window-size))
 348         (scroll-up nil)
 349       (if (>= (- lines) (view-window-size))
 350           (scroll-down nil)
 351         (scroll-up lines)))
 352     (cond ((pos-visible-in-window-p (point-max))
 353            (goto-char (point-max))
 354            (message "%s"
 355                     (substitute-command-keys
 356                      "End.  Type \\[view-exit] to quit viewing."))))
 357     (move-to-window-line -1)
 358     (beginning-of-line)))
 359
 360 (defun View-scroll-lines-forward-set-scroll-size (&optional lines)
 361   "Scroll forward LINES lines in View mode, setting the \"scroll size\".
 362 This is the number of lines which \\[View-scroll-lines-forward] and \\[View-scroll-lines-backward] scroll by default.
 363 The absolute value of LINES is used, so this command can be used to scroll
 364 backwards (but \"scroll size\" is always positive).  If LINES is greater than
 365 window height or omitted, then window height is assumed.  If LINES is less
 366 than window height then scrolling context is provided from previous screen."
 367   (interactive "P")
 368   (if (not lines)
 369       (setq view-scroll-size (view-window-size))
 370     (setq lines (prefix-numeric-value lines))
 371     (setq view-scroll-size
 372           (min (if (> lines 0) lines (- lines)) (view-window-size))))
 373   (View-scroll-lines-forward lines))
 374
 375 (defun View-scroll-one-more-line (&optional arg)
 376   "Scroll one more line up in View mode.
 377 With ARG scroll one line down."
 378   (interactive "P")
 379   (View-scroll-lines-forward (if (not arg) 1 -1)))
 380
 381 (defun View-scroll-lines-backward (&optional lines)
 382   "Scroll backward in View mode.
 383 No arg means whole window full, or number of lines set by \\[View-scroll-lines-forward-set-scroll-size].
 384 Arg is number of lines to scroll."
 385   (interactive "P")
 386   (View-scroll-lines-forward (if lines
 387                                  (- (prefix-numeric-value lines))
 388                                (- (view-scroll-size)))))
 389
 390 (defun View-search-regexp-forward (n regexp)
 391   "Search forward for Nth occurrence of REGEXP.
 392 Displays line found at center of window.  REGEXP is remembered for
 393 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
 394
 395 The variable `view-highlight-face' controls the face that is used
 396 for highlighting the match that is found."
 397   (interactive "p\nsSearch forward (regexp): ")
 398 ;;;(view-last-command 'View-search-last-regexp-forward n)
 399   (view-search n (if (equal regexp "") view-last-regexp regexp)))
 400
 401 (defun View-search-regexp-backward (n regexp)
 402   "Search backward from window start for Nth instance of REGEXP.
 403 Displays line found at center of window.  REGEXP is remembered for
 404 searching with \\[View-search-last-regexp-forward] and \\[View-search-last-regexp-backward].  Sets mark at starting position and pushes mark ring.
 405
 406 The variable `view-highlight-face' controls the face that is used
 407 for highlighting the match that is found."
 408   (interactive "p\nsSearch backward (regexp): ")
 409   (View-search-regexp-forward (- n)
 410                               (if (equal regexp "") view-last-regexp regexp)))
 411
 412 (defun View-search-last-regexp-forward (n)
 413   "Search forward from window end for Nth instance of last regexp.
 414 Displays line found at center of window.  Sets mark at starting position
 415 and pushes mark ring.
 416
 417 The variable `view-highlight-face' controls the face that is used
 418 for highlighting the match that is found."
 419   (interactive "p")
 420   (if view-last-regexp
 421       (View-search-regexp-forward n view-last-regexp)
 422     (error "No previous View-mode search")))
 423
 424 (defun View-search-last-regexp-backward (n)
 425   "Search backward from window start for Nth instance of last regexp.
 426 Displays line found at center of window.  Sets mark at starting position and
 427 pushes mark ring.
 428
 429 The variable `view-highlight-face' controls the face that is used
 430 for highlighting the match that is found."
 431   (interactive "p")
 432   (if view-last-regexp
 433       (View-search-regexp-backward n view-last-regexp)
 434     (error "No previous View-mode search")))
 435
 436 (defun View-back-to-mark (&optional ignore)
 437   "Return to last mark set in View mode, else beginning of file.
 438 Displays line at center of window.  Pops mark ring so successive
 439 invocations return to earlier marks."
 440   (interactive)
 441   (goto-char (or (mark t) (point-min)))
 442   (pop-mark)
 443   (recenter (/ (view-window-size) 2)))
 444
 445 (defun view-search (times regexp)
 446   (setq view-last-regexp regexp)
 447   (let (where)
 448     (save-excursion
 449       (move-to-window-line (if (< times 0) 0 -1))
 450       (if (re-search-forward regexp nil t times)
 451           (setq where (point))))
 452     (if where
 453         (progn
 454           (push-mark)
 455           (goto-char where)
 456           (if view-overlay
 457               (move-overlay view-overlay (match-beginning 0) (match-end 0))
 458             (setq view-overlay
 459                   (make-overlay (match-beginning 0) (match-end 0))))
 460           (overlay-put view-overlay 'face view-highlight-face)
 461           (beginning-of-line)
 462           (recenter (/ (view-window-size) 2)))
 463       (message "Can't find occurrence %d of %s" times regexp)
 464       (sit-for 4))))
 465
 466 \f
 467 (provide 'view)
 468
 469 ;;; view.el ends here