code.delx.au - gnu-emacs/blob - lisp/textmodes/two-column.el

   1 ;;; two-column.el --- minor mode for editing of two-column text
   2
   3 ;; Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   4
   5 ;; Author: Daniel.Pfeiffer@Informatik.START.dbp.de, fax (+49 69) 7588-2389
   6 ;; Adapted-By: ESR, Daniel Pfeiffer
   7
   8 ;; Esperanto:                            English:
   9
  10 ;; ^Ci dosiero estas ero de GNU Emacs.   This file is part of GNU Emacs.
  11
  12 ;; GNU  Emacs estas libera  programaro;  GNU Emacs is free software; you can
  13 ;; vi povas disdoni ^gin kaj/a^u modifi  redistribute it and/or modify it
  14 ;; ^gin sub  la  kondi^coj  de  la  GNU  under the terms of the GNU General
  15 ;; ^Generala  Publika Licenco kiel pub-  Public License as published by the
  16 ;; likigita far la Liberprogramara Fon-  Free Software Foundation; either
  17 ;; da^jo; a^u eldono 2a,  a^u (la^u via  version 2, or (at your option) any
  18 ;; elekto) ajna posta eldono.            later version.
  19
  20 ;; GNU  Emacs  estas  disdonata  en  la  GNU Emacs is distributed in the hope
  21 ;; espero ke  ^gi estos utila,  sed SEN  that it will be useful, but WITHOUT
  22 ;; IA  GARANTIO;  sen e^c  la implicita  ANY WARRANTY; without even the
  23 ;; garantio  de VENDEBLECO  a^u PRETECO  implied warranty of MERCHANTABILITY
  24 ;; POR  DETERMINITA CELO.  Vidu la  GNU  or FITNESS FOR A PARTICULAR PURPOSE.
  25 ;; ^Generala Publika Licenco por plenaj  See the GNU General Public License
  26 ;; detaloj.                              for more details.
  27
  28 ;; Vi devus ricevinti kopion de la  GNU  You should have received a copy of
  29 ;; ^Generala  Publika  Licenco kune kun  the GNU General Public License along
  30 ;; GNU Emacs; vidu la dosieron COPYING.  with GNU Emacs; see the file
  31 ;; Alikaze skribu al la                  COPYING.  If not, write to the
  32
  33 ;; Free Software Foundation, 59 Temple Place - Suite 330
  34 ;; Boston, MA 02111-1307, USA.
  35
  36
  37 ;;; Komentario:                          Commentary:
  38
  39 ;; Tiu  programaro ebligas  vin redakti  This package gives you the ability
  40 ;; dukolumnan tekston.                   to edit text in a two-column format.
  41
  42
  43 ;; Vi  havas  tri eblecojn por eki tiun  You have three ways to start up this
  44 ;; mal^cefan modalon.  ^Ciu donas al vi  minor mode.  Each gives you a
  45 ;; horizontale disigatan fenestron, si-  horizontally split window similar to
  46 ;; milan al fina apareco de via teksto:  the final outcome of your text:
  47
  48
  49 ;; f2 2     asocias  novan  bufron  nomatan  associates a new  buffer called
  50 ;; C-x 6 2  same, sed kun 2C/ anta^u.        the   same,    but   with   2C/
  51 ;;                                           prepended.
  52
  53 ;; f2 b     asocias alian bufron.  Vi povas  associates    another   buffer.
  54 ;; C-x 6 b  anka^u asocii  dataron,   se vi  This can be used to associate a
  55 ;;          ^jus anta^ue faris C-x C-f.      file if you just did C-x C-f.
  56
  57 ;; f2 s     disigas  jam dukolumnan tekston  splits a  two-column  text into
  58 ;; C-x 6 s  en  du   bufroj  ekde  la  nuna  two  buffers from  the  current
  59 ;;          linio,  kaj je la nuna kolumno.  line and at the current column.
  60 ;;          La    anta^uaj   signoj   (ofte  The preceding characters (often
  61 ;;          tabeligilo  a^u  |)  estas   la  tab   or  |)  are   the  column
  62 ;;          kolumna disiganto.  Linioj kiuj  separator.   Lines  that  don't
  63 ;;          ne   enhavas   ilin   ne  estas  have them  won't  be separated.
  64 ;;          disigitaj.   Kiel  la kvara kaj  Like the  fourth and fifth line
  65 ;;          la   kvina  linio se vi disigas  if  you split this  file from
  66 ;;          ^ci dataron ekde la unua  angla  the first english word.
  67 ;;          vorto.
  68
  69 ;; Se  vi  volas  meti  longajn liniojn  If you include long lines, i.e which
  70 ;; (ekz. programerojn) en la  kunigotan  will span both columns  (eg.  source
  71 ;; tekston,   ili  devas  esti  en   la  code), they should  be  in what will
  72 ;; estonte unua kolumno.  La alia devas  be the    first column,    with  the
  73 ;; havi vakajn linion apud ili.          associated buffer having empty lines
  74 ;;                                       next to them.
  75
  76 ;; Averto: en Emacs kiam vi ^san^gas la  Attention:  in Emacs when you change
  77 ;; ^cefan modalon, la mal^cefaj modaloj  the major mode,  the minor modes are
  78 ;; estas  anka^u  elmemorigitaj.   Tiu-  also  purged  from  memory.  In that
  79 ;; okaze  vi devas religi la du bufrojn  case you   must  reassociate the two
  80 ;; per iu  C-x 6-ordono,  ekz. C-x 6 b.  buffers with any C-x 6-command, e.g.
  81 ;;                                       C-x 6 b.
  82
  83 ;; Kiam   vi   estos  kontenta   de  la  When you have edited both buffers to
  84 ;; rezulto, vi kunmetos la du kolumnojn  your  content,  you merge them  with
  85 ;; per  C-x 6 1.   Se  vi  poste  vidas  C-x 6 1.  If you then see a problem,
  86 ;; problemon, vi  neniigu   la kunmeton  you undo the  merge with  C-x u  and
  87 ;; per C-x u  kaj  plue  modifu  la  du  continue   to  edit the two buffers.
  88 ;; bufrojn.  Kiam vi ne plu volas tajpi  When you  no longer  want to edit in
  89 ;; dukolumne,  vi  eliru el la mal^cefa  two  columns, you turn off the minor
  90 ;; modalo per C-x 6 d.                   mode with C-x 6 d.
  91
  92
  93 ;; Aldone al dukolumna  redaktado,  ek-  In addition to two-column editing of
  94 ;; zemple por  skribi dulingvan tekston  text, for example for writing a
  95 ;; flank-al-flanke kiel ^ci tiu,  aliaj  bilingual text side-by-side as shown
  96 ;; interesaj uzoj trovitas por tiu mal-  here, other interesting uses have
  97 ;; ^cefa modalo:                         been found for this minor mode:
  98
  99 ;; Vi povas  disigi la  kolumnojn per {+} You can separate the columns with
 100 ;; ajna   pla^ca   ^ceno   starigante {+} any string that pleases you, by
 101 ;; `2C-separator'.   Ekzemple  "{+} " {+} setting `2C-separator'.  For example
 102 ;; por  amuzi^gi.  f2 s  a^u  C-x 6 s {+} "{+} " if you'd like to have fun.
 103 ;; traktas   tiujn    kun    prefiksa {+} f2 s or C-x 6 s handles these with a
 104 ;; argumento  kiu  signifas la longon {+} prefix argument that means the
 105 ;; de tia ^ceno.                      {+} desired length of such a string.
 106
 107
 108 ;; Programistoj eble ^satus la  eblecon  Programmers might like the ability
 109 ;; forspliti la komentarian kolumnon de  to split off the comment column of a
 110 ;; dosiero  kiel la sekvanta.  Vi povas  file that looks like the following.
 111 ;; rearan^gigi  la paragrafon.  La pro-  You can fill-paragraph the comment.
 112 ;; blemo  estas  ke  koda^jo tuj   lar-  The problem is, code quickly gets
 113 ;; ^gi^gas,  tiel  ke vi  bezonas   pli  rather wide, so you need to use a
 114 ;; mallar^gan   komentarian   kolumnon.  narrower comment column.  Code lines
 115 ;; Koda^jaj linioj tra `comment-column'  that reach beyond `comment-column'
 116 ;; ne problemas,  krom  ke vi ne  vidos  are no problem, except that you
 117 ;; iliajn finojn dum redaktado.          won't see their end during editing.
 118
 119
 120 ;; BEGIN                                -- This is just some meaningless
 121 ;;     FOR i IN 1..10 LOOP              -- code in Ada, that runs foobar
 122 ;;         foobar( i );                 -- once for each argument from one
 123 ;;     END LOOP;                        -- to ten, and then we're already
 124 ;; END;                                 -- through with it.
 125
 126 ;; Pli bone ankora^u, vi povas  pozici-  Better yet, you can put the point
 127 ;; i^gi anta^u "This",  tajpi  M-3 f2 s  before "This", type  M-3 f2 s
 128 ;; kiu  igas "-- " la separigilon inter  which makes "-- " the separator
 129 ;; senkomentaria  Ada  bufro  kaj  nur-  between a no-comments Ada buffer,
 130 ;; teksta  komentaria  bufro.   Kiam vi  and a plain text comment buffer.
 131 ;; denove  kuni^gos ilin,  ^ciu  nevaka  When you put them back together,
 132 ;; linio  de  l'  dua  kolumno   denove  every non-empty line of the 2nd
 133 ;; anta^uhavos "-- ".                    column will again be preceded by
 134 ;;                                       "-- ".
 135
 136
 137 ;;; Code:
 138 \f
 139
 140 ;; Lucid patch
 141 (or (fboundp 'frame-width)
 142     (fset 'frame-width 'screen-width))
 143
 144
 145 ;;;;; Set up keymap ;;;;;
 146
 147 (defvar 2C-mode-map
 148   (let ((map (make-sparse-keymap)))
 149     (define-key map "2" '2C-two-columns)
 150     (define-key map [f2] '2C-two-columns)
 151     (define-key map "b" '2C-associate-buffer)
 152     (define-key map "s" '2C-split)
 153     map)
 154   "Keymap for commands for setting up two-column mode.")
 155
 156
 157
 158 ;;;###autoload (autoload '2C-command "two-column" () t 'keymap)
 159 (fset '2C-command 2C-mode-map)
 160
 161 ;;;###autoload
 162 ;; This one is for historical reasons and simple keyboards, it is not
 163 ;; at all mnemonic.  All usual sequences containing 2 were used, and
 164 ;; f2 could not be set up in a standard way under Emacs 18.
 165 (global-set-key "\C-x6" '2C-command)
 166
 167
 168 ;;;###autoload
 169 (global-set-key [f2] '2C-command)
 170
 171
 172 (defvar 2C-minor-mode-map
 173   (let ((map (make-sparse-keymap)))
 174     (define-key map "1" '2C-merge)
 175     (define-key map "d" '2C-dissociate)
 176     (define-key map "o" '2C-associated-buffer)
 177     (define-key map "\^m" '2C-newline)
 178     (define-key map "|" '2C-toggle-autoscroll)
 179     (define-key map "{" '2C-shrink-window-horizontally)
 180     (define-key map "}" '2C-enlarge-window-horizontally)
 181     map)
 182   "Keymap for commands for use in two-column mode.")
 183
 184
 185 (setq minor-mode-map-alist
 186       (cons (cons '2C-mode
 187                   (let ((map (make-sparse-keymap)))
 188                     (substitute-key-definition '2C-command 2C-minor-mode-map
 189                                                map (current-global-map))
 190                     (substitute-key-definition 'enlarge-window-horizontally
 191                                                '2C-enlarge-window-horizontally
 192                                                map (current-global-map))
 193                     (substitute-key-definition 'shrink-window-horizontally
 194                                                '2C-shrink-window-horizontally
 195                                                map (current-global-map))
 196                     map))
 197             minor-mode-map-alist))
 198 \f
 199 ;;;;; variable declarations ;;;;;
 200
 201 ;; Markers seem to be the only buffer-id not affected by renaming a buffer.
 202 ;; This nevertheless loses when a buffer is killed.  The variable-name is
 203 ;; required by `describe-mode'.
 204 (defvar 2C-mode nil
 205   "Marker to the associated buffer, if non-nil.")
 206 (make-variable-buffer-local '2C-mode)
 207 (put '2C-mode 'permanent-local t)
 208
 209
 210
 211 (setq minor-mode-alist (cons '(2C-mode " 2C") minor-mode-alist))
 212
 213
 214
 215 ;; rearranged, so that the pertinent info will show in 40 columns
 216 (defvar 2C-mode-line-format
 217         '("-%*- %15b --"  (-3 . "%p")  "--%[("  mode-name
 218           minor-mode-alist  "%n"  mode-line-process  ")%]%-")
 219   "*Value of mode-line-format for a buffer in two-column minor mode.")
 220
 221
 222 (defvar 2C-other-buffer-hook 'text-mode
 223   "*Hook run in new buffer when it is associated with current one.")
 224
 225
 226 (defvar 2C-separator ""
 227   "*A string inserted between the two columns when merging.
 228 This gets set locally by \\[2C-split].")
 229 (put '2C-separator 'permanent-local t)
 230
 231
 232
 233 (defvar 2C-window-width 40
 234   "*The width of the first column.  (Must be at least `window-min-width')
 235 This value is local for every buffer that sets it.")
 236 (make-variable-buffer-local '2C-window-width)
 237 (put '2C-window-width 'permanent-local t)
 238
 239
 240
 241 (defvar 2C-beyond-fill-column 4
 242   "*Base for calculating `fill-column' for a buffer in two-column minor mode.
 243 The value of `fill-column' becomes `2C-window-width' for this buffer
 244 minus this value.")
 245
 246
 247
 248 (defvar 2C-autoscroll t
 249   "If non-nil, Emacs attempts to keep the two column's buffers aligned.")
 250
 251
 252
 253 (defvar 2C-autoscroll-start nil)
 254 (make-variable-buffer-local '2C-autoscroll-start)
 255 \f
 256 ;;;;; base functions ;;;;;
 257
 258 ;; The access method for the other buffer.  This tries to remedy against
 259 ;; lost local variables and lost buffers.
 260 (defun 2C-other (&optional req)
 261   (or (if 2C-mode
 262           (or (prog1
 263                   (marker-buffer 2C-mode)
 264                 (setq mode-line-format 2C-mode-line-format))
 265               ;; The associated buffer somehow got killed.
 266               (progn
 267                 ;; The other variables may later be useful if the user
 268                 ;; reestablishes the association.
 269                 (kill-local-variable '2C-mode)
 270                 (kill-local-variable 'mode-line-format)
 271                 nil)))
 272       (if req (error "You must first set two-column minor mode."))))
 273
 274
 275
 276 ;; function for setting up two-column minor mode in a buffer associated
 277 ;; with the buffer pointed to by the marker other.
 278 (defun 2C-mode (other)
 279   "Minor mode for independently editing two columns.
 280 This is set up for two associated buffers by the three commands bound
 281 to  \\[2C-two-columns] ,  \\[2C-associate-buffer]  and  \\[2C-split].
 282 Turning on two-column mode calls the value of the variable `2C-mode-hook',
 283 if that value is non-nil.
 284
 285 These buffers can be edited separately, for example with `fill-paragraph'.
 286 If you want to disable parallel scrolling temporarily, use  \\[2C-toggle-autoscroll] .
 287
 288 If you include long lines, i.e which will span both columns (eg.
 289 source code), they should be in what will be the first column, with
 290 the associated buffer having empty lines next to them.
 291
 292 Potential uses are writing bilingual texts, or editing the comments of a
 293 source code.  See the file lisp/two-column.el for detailed examples.
 294
 295 You have the following commands at your disposal:
 296
 297 \\[2C-two-columns]   Rearrange screen with current buffer first
 298 \\[2C-associate-buffer]   Reassociate buffer after changing major mode
 299 \\[shrink-window-horizontally], \\[enlarge-window-horizontally]   Shrink, enlarge current column
 300 \\[2C-associated-buffer]   Switch to associated buffer at same point
 301 \\[2C-newline] Insert newline(s) in both buffers at same point
 302 \\[2C-merge]   Merge both buffers
 303 \\[2C-dissociate]   Dissociate the two buffers
 304
 305 These keybindings can be customized in your ~/.emacs by `2C-mode-map',
 306 `2C-minor-mode-map' and by binding `2C-command' to some prefix.
 307
 308 The appearance of the screen can be customized by the variables
 309 `2C-window-width', `2C-beyond-fill-column', `2C-mode-line-format' and
 310 `truncate-partial-width-windows'."
 311   (make-local-hook 'post-command-hook)
 312   (add-hook 'post-command-hook '2C-autoscroll nil t)
 313   (setq fill-column (- 2C-window-width
 314                        2C-beyond-fill-column)
 315         mode-line-format 2C-mode-line-format
 316         2C-mode other)
 317   (run-hooks '2C-mode-hook))
 318
 319
 320
 321 ;;;###autoload
 322 (defun 2C-two-columns (&optional buffer)
 323   "Split current window vertically for two-column editing.
 324 When called the first time, associates a buffer with the current
 325 buffer in two-column minor mode (see  \\[describe-mode] ).
 326 Runs `2C-other-buffer-hook' in the new buffer.
 327 When called again, restores the screen layout with the current buffer
 328 first and the associated buffer to it's right."
 329   (interactive "P")
 330   ;; first go to full width, so that we can certainly split into two windows
 331   (if (< (window-width) (frame-width))
 332       (enlarge-window 99999 t))
 333   (split-window-horizontally
 334    (max window-min-width (min 2C-window-width
 335                               (- (frame-width) window-min-width))))
 336   (if (2C-other)
 337       (progn
 338         (other-window 1)
 339         (switch-to-buffer (2C-other))
 340         (other-window -1)
 341         (if 2C-autoscroll
 342             (2C-toggle-autoscroll t)))
 343
 344     (2C-mode (prog1 (point-marker)
 345                (other-window 1)
 346                (switch-to-buffer
 347                 (or buffer
 348                     (generate-new-buffer (concat "2C/" (buffer-name)))))
 349                (or buffer
 350                    (run-hooks '2C-other-buffer-hook))))
 351
 352     (2C-mode (prog1 (point-marker)
 353                (other-window -1)))))
 354
 355
 356
 357 ;;;###autoload
 358 (defun 2C-associate-buffer ()
 359   "Associate another buffer with this one in two-column minor mode.
 360 Can also be used to associate a just previously visited file, by
 361 accepting the proposed default buffer.
 362
 363 \(See  \\[describe-mode] .)"
 364   (interactive)
 365   (let ((b1 (current-buffer))
 366         (b2 (or (2C-other)
 367                 (read-buffer "Associate buffer: " (other-buffer)))))
 368     (save-excursion
 369       (setq 2C-mode nil)
 370       (set-buffer b2)
 371       (and (2C-other)
 372            (not (eq b1 (2C-other)))
 373            (error "Buffer already associated with buffer `%s'."
 374                   (buffer-name (2C-other))))
 375       (setq b1 (and (assq '2C-window-width (buffer-local-variables))
 376                     2C-window-width)))
 377     ; if other buffer has a local width, adjust here too
 378     (if b1 (setq 2C-window-width (- (frame-width) b1)))
 379     (2C-two-columns b2)))
 380
 381
 382
 383 ;;;###autoload
 384 (defun 2C-split (arg)
 385   "Split a two-column text at point, into two buffers in two-column minor mode.
 386 Point becomes the local value of `2C-window-width'.  Only lines that
 387 have the ARG same preceding characters at that column get split.  The
 388 ARG preceding characters without any leading whitespace become the local
 389 value for `2C-separator'.  This way lines that continue across both
 390 columns remain untouched in the first buffer.
 391
 392 This function can be used with a prototype line, to set up things.  You
 393 write the first line of each column and then split that line.  E.g.:
 394
 395 First column's text    sSs  Second column's text
 396                        \\___/\\
 397                         /    \\
 398    5 character Separator      You type  M-5 \\[2C-split]  with the point here.
 399
 400 \(See  \\[describe-mode] .)"
 401   (interactive "*p")
 402   (and (2C-other)
 403        (if (y-or-n-p (concat "Overwrite associated buffer `"
 404                              (buffer-name (2C-other))
 405                              "'? "))
 406            (save-excursion
 407              (set-buffer (2C-other))
 408              (erase-buffer))
 409          (signal 'quit nil)))
 410   (let ((point (point))
 411         ; make next-line always come back to same column
 412         (goal-column (current-column))
 413         ; a counter for empty lines in other buffer
 414         (n (1- (count-lines (point-min) (point))))
 415         chars other)
 416     (save-excursion
 417       (backward-char arg)
 418       (setq chars (buffer-substring (point) point))
 419       (skip-chars-forward " \t" point)
 420       (make-local-variable '2C-separator)
 421       (setq 2C-separator (buffer-substring (point) point)
 422             2C-window-width (current-column)))
 423     (2C-two-columns)
 424     (setq other (2C-other))
 425     ; now we're ready to actually split
 426     (save-excursion
 427       (while (not (eobp))
 428         (if (not (and (= (current-column) goal-column)
 429                       (string= chars
 430                                (buffer-substring (point)
 431                                                  (save-excursion
 432                                                    (backward-char arg)
 433                                                    (point))))))
 434             (setq n (1+ n))
 435           (setq point (point))
 436           (backward-char arg)
 437           (skip-chars-backward " \t")
 438           (delete-region point (point))
 439           (setq point (point))
 440           (insert-char ?\n n)
 441           (append-to-buffer other point (progn (end-of-line)
 442                                                (if (eobp)
 443                                                    (point)
 444                                                  (1+ (point)))))
 445           (delete-region point (point))
 446           (setq n 0))
 447         (next-line 1)))))
 448
 449
 450
 451
 452 (defun 2C-dissociate ()
 453   "Turn off two-column minor mode in current and associated buffer.
 454 If the associated buffer is unmodified and empty, it is killed."
 455   (interactive)
 456   (let ((buffer (current-buffer)))
 457     (save-excursion
 458       (and (2C-other)
 459            (set-buffer (2C-other))
 460            (or (not (2C-other))
 461                (eq buffer (2C-other)))
 462            (if (and (not (buffer-modified-p))
 463                     (eobp) (bobp))
 464                (kill-buffer nil)
 465              (kill-local-variable '2C-mode)
 466              (kill-local-variable '2C-window-width)
 467              (kill-local-variable '2C-separator)
 468              (kill-local-variable 'mode-line-format)
 469              (kill-local-variable 'fill-column))))
 470     (kill-local-variable '2C-mode)
 471     (kill-local-variable '2C-window-width)
 472     (kill-local-variable '2C-separator)
 473     (kill-local-variable 'mode-line-format)
 474     (kill-local-variable 'fill-column)))
 475
 476
 477
 478 ;; this doesn't use yank-rectangle, so that the first column can
 479 ;; contain long lines
 480 (defun 2C-merge ()
 481   "Merges the associated buffer with the current buffer.
 482 They get merged at the column, which is the value of `2C-window-width',
 483 i.e. usually at the vertical window separator.  This separator gets
 484 replaced with white space.  Beyond that the value of `2C-separator' gets
 485 inserted on merged lines.  The two columns are thus pasted side by side,
 486 in a single text.  If the other buffer is not displayed to the left of
 487 this one, then this one becomes the left column.
 488
 489 If you want `2C-separator' on empty lines in the second column,
 490 you should put just one space in them.  In the final result, you can strip
 491 off trailing spaces with \\[beginning-of-buffer] \\[replace-regexp] [ SPC TAB ] + $ RET RET"
 492   (interactive)
 493   (and (> (car (window-edges)) 0)       ; not touching left edge of screen
 494        (eq (window-buffer (previous-window))
 495            (2C-other t))
 496        (other-window -1))
 497   (save-excursion
 498     (let ((b1 (current-buffer))
 499           (b2 (2C-other t))
 500           string)
 501       (goto-char (point-min))
 502       (set-buffer b2)
 503       (goto-char (point-min))
 504       (while (not (eobp))
 505         (setq string (buffer-substring (point)
 506                                        (progn (end-of-line) (point))))
 507         (or (eobp)
 508             (forward-char))             ; next line
 509         (set-buffer b1)
 510         (if (string= string "")
 511             ()
 512           (end-of-line)
 513           (indent-to-column 2C-window-width)
 514           (insert 2C-separator string))
 515         (next-line 1)                   ; add one if necessary
 516         (set-buffer b2))))
 517   (if (< (window-width) (frame-width))
 518       (enlarge-window 99999 t)))
 519 \f
 520 ;;;;; utility functions ;;;;;
 521
 522 (defun 2C-associated-buffer ()
 523   "Switch to associated buffer."
 524   (interactive)
 525   (let ((line (+ (count-lines (point-min) (point))
 526                  (if (bolp) 1 0)))
 527         (col (if (eolp) (if (bolp) 0) (current-column))))
 528     (if (get-buffer-window (2C-other t))
 529         (select-window (get-buffer-window (2C-other)))
 530       (switch-to-buffer (2C-other)))
 531     (newline (goto-line line))
 532     (if col
 533         (move-to-column col)
 534       (end-of-line 1))))
 535
 536 (defun 2C-newline (arg)
 537   "Insert ARG newlines in both buffers."
 538   (interactive "P")
 539   (save-window-excursion
 540     (2C-associated-buffer)
 541     (newline arg))
 542   (newline arg))
 543
 544 (defun 2C-toggle-autoscroll (arg)
 545   "Toggle autoscrolling, or set it iff prefix ARG is non-nil and positive.
 546 When autoscrolling is turned on, this also realigns the two buffers."
 547   (interactive "P")
 548   ;(sit-for 0)
 549   (setq 2C-autoscroll-start (window-start))
 550   (if (setq 2C-autoscroll (if arg
 551                               (>= (prefix-numeric-value arg) 0)
 552                             (not 2C-autoscroll)))
 553       (select-window
 554        (prog1 (selected-window)
 555          (message "Autoscrolling is on.")
 556          (setq arg (count-lines (point-min) (window-start)))
 557          (if (get-buffer-window (2C-other t))
 558              (progn
 559                (select-window (get-buffer-window (2C-other)))
 560                (setq arg (- arg (count-lines (point-min) (window-start))))
 561                ;; make sure that other buffer has enough lines
 562                (save-excursion
 563                  (insert-char ?\n
 564                               (- arg (count-lines (window-start)
 565                                                   (goto-char (point-max)))
 566                                  -1)))
 567                (scroll-up arg)))))
 568     (message "Autoscrolling is off.")))
 569
 570
 571
 572 (defun 2C-autoscroll ()
 573   (if 2C-autoscroll
 574       ;; catch a mouse scroll on non-selected scrollbar
 575       (select-window
 576        (prog1 (selected-window)
 577          (and (consp last-command-char)
 578               (not (eq (selected-window)
 579                        (car (car (cdr last-command-char)))))
 580               (select-window (car (car (cdr last-command-char)))))
 581          ;; In some cases scrolling causes an error, but post-command-hook
 582          ;; shouldn't, and should always stay in the original window
 583          (condition-case ()
 584              (and (or 2C-autoscroll-start (2C-toggle-autoscroll t) nil)
 585                   (/= (window-start) 2C-autoscroll-start)
 586                   (2C-other)
 587                   (get-buffer-window (2C-other))
 588                   (let ((lines (count-lines (window-start)
 589                                             2C-autoscroll-start)))
 590                     (if (< (window-start) 2C-autoscroll-start)
 591                         (setq lines (- lines)))
 592                     (setq 2C-autoscroll-start (window-start))
 593                     (select-window (get-buffer-window (2C-other)))
 594                     ;; make sure that other buffer has enough lines
 595                     (save-excursion
 596                       (insert-char
 597                        ?\n (- lines (count-lines (window-start)
 598                                                  (goto-char (point-max)))
 599                               -1)))
 600                     (scroll-up lines)
 601                     (setq 2C-autoscroll-start (window-start))))
 602            (error))))))
 603
 604
 605
 606 (defun 2C-enlarge-window-horizontally (arg)
 607   "Make current window ARG columns wider."
 608   (interactive "p")
 609   (enlarge-window arg t)
 610   (and (2C-other)
 611        (setq 2C-window-width (+ 2C-window-width arg))
 612        (set-buffer (2C-other))
 613        (setq 2C-window-width (- 2C-window-width arg))))
 614
 615 (defun 2C-shrink-window-horizontally (arg)
 616   "Make current window ARG columns narrower."
 617   (interactive "p")
 618   (2C-enlarge-window-horizontally (- arg)))
 619
 620
 621
 622 (provide 'two-column)
 623
 624 ;;; two-column.el ends here