lisp/view.el

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