lisp/textmodes/outline.el

   1 ;;; outline.el --- outline mode commands for Emacs
   2
   3 ;; Copyright (C) 1986, 93, 94, 95, 97, 2000 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: outlines
   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 is a major mode for editing outline-format documents.
  28 ;; An outline can be `abstracted' to show headers at any given level,
  29 ;; with all stuff below hidden.  See the Emacs manual for details.
  30
  31 ;;; Todo:
  32
  33 ;; - subtree-terminators
  34
  35 ;;; Code:
  36
  37 (defgroup outlines nil
  38   "Support for hierarchical outlining"
  39   :prefix "outline-"
  40   :group 'editing)
  41
  42 (defcustom outline-regexp nil
  43   "*Regular expression to match the beginning of a heading.
  44 Any line whose beginning matches this regexp is considered to start a heading.
  45 The recommended way to set this is with a Local Variables: list
  46 in the file it applies to.  See also `outline-heading-end-regexp'."
  47   :type '(choice regexp (const nil))
  48   :group 'outlines)
  49
  50 ;; Can't initialize this in the defvar above -- some major modes have
  51 ;; already assigned a local value to it.
  52 (or (default-value 'outline-regexp)
  53     (setq-default outline-regexp "[*\^L]+"))
  54
  55 (defcustom outline-heading-end-regexp "\n"
  56   "*Regular expression to match the end of a heading line.
  57 You can assume that point is at the beginning of a heading when this
  58 regexp is searched for.  The heading ends at the end of the match.
  59 The recommended way to set this is with a `Local Variables:' list
  60 in the file it applies to."
  61   :type 'regexp
  62   :group 'outlines)
  63
  64 (defvar outline-mode-prefix-map nil)
  65
  66 (if outline-mode-prefix-map
  67     nil
  68   (setq outline-mode-prefix-map (make-sparse-keymap))
  69   (define-key outline-mode-prefix-map "@" 'outline-mark-subtree)
  70   (define-key outline-mode-prefix-map "\C-n" 'outline-next-visible-heading)
  71   (define-key outline-mode-prefix-map "\C-p" 'outline-previous-visible-heading)
  72   (define-key outline-mode-prefix-map "\C-i" 'show-children)
  73   (define-key outline-mode-prefix-map "\C-s" 'show-subtree)
  74   (define-key outline-mode-prefix-map "\C-d" 'hide-subtree)
  75   (define-key outline-mode-prefix-map "\C-u" 'outline-up-heading)
  76   (define-key outline-mode-prefix-map "\C-f" 'outline-forward-same-level)
  77   (define-key outline-mode-prefix-map "\C-b" 'outline-backward-same-level)
  78   (define-key outline-mode-prefix-map "\C-t" 'hide-body)
  79   (define-key outline-mode-prefix-map "\C-a" 'show-all)
  80   (define-key outline-mode-prefix-map "\C-c" 'hide-entry)
  81   (define-key outline-mode-prefix-map "\C-e" 'show-entry)
  82   (define-key outline-mode-prefix-map "\C-l" 'hide-leaves)
  83   (define-key outline-mode-prefix-map "\C-k" 'show-branches)
  84   (define-key outline-mode-prefix-map "\C-q" 'hide-sublevels)
  85   (define-key outline-mode-prefix-map "\C-o" 'hide-other))
  86
  87 (defvar outline-mode-menu-bar-map nil)
  88 (if outline-mode-menu-bar-map
  89     nil
  90   (setq outline-mode-menu-bar-map (make-sparse-keymap))
  91
  92   (define-key outline-mode-menu-bar-map [hide]
  93     (cons "Hide" (make-sparse-keymap "Hide")))
  94
  95   (define-key outline-mode-menu-bar-map [hide hide-other]
  96     '("Hide Other" . hide-other))
  97   (define-key outline-mode-menu-bar-map [hide hide-sublevels]
  98     '("Hide Sublevels" . hide-sublevels))
  99   (define-key outline-mode-menu-bar-map [hide hide-subtree]
 100     '("Hide Subtree" . hide-subtree))
 101   (define-key outline-mode-menu-bar-map [hide hide-entry]
 102     '("Hide Entry" . hide-entry))
 103   (define-key outline-mode-menu-bar-map [hide hide-body]
 104     '("Hide Body" . hide-body))
 105   (define-key outline-mode-menu-bar-map [hide hide-leaves]
 106     '("Hide Leaves" . hide-leaves))
 107
 108   (define-key outline-mode-menu-bar-map [show]
 109     (cons "Show" (make-sparse-keymap "Show")))
 110
 111   (define-key outline-mode-menu-bar-map [show show-subtree]
 112     '("Show Subtree" . show-subtree))
 113   (define-key outline-mode-menu-bar-map [show show-children]
 114     '("Show Children" . show-children))
 115   (define-key outline-mode-menu-bar-map [show show-branches]
 116     '("Show Branches" . show-branches))
 117   (define-key outline-mode-menu-bar-map [show show-entry]
 118     '("Show Entry" . show-entry))
 119   (define-key outline-mode-menu-bar-map [show show-all]
 120     '("Show All" . show-all))
 121
 122   (define-key outline-mode-menu-bar-map [headings]
 123     (cons "Headings" (make-sparse-keymap "Headings")))
 124
 125   (define-key outline-mode-menu-bar-map [headings copy]
 126     '(menu-item "Copy to kill ring" outline-headers-as-kill
 127                 :enable mark-active))
 128   (define-key outline-mode-menu-bar-map [headings outline-backward-same-level]
 129     '("Previous Same Level" . outline-backward-same-level))
 130   (define-key outline-mode-menu-bar-map [headings outline-forward-same-level]
 131     '("Next Same Level" . outline-forward-same-level))
 132   (define-key outline-mode-menu-bar-map [headings outline-previous-visible-heading]
 133     '("Previous" . outline-previous-visible-heading))
 134   (define-key outline-mode-menu-bar-map [headings outline-next-visible-heading]
 135     '("Next" . outline-next-visible-heading))
 136   (define-key outline-mode-menu-bar-map [headings outline-up-heading]
 137     '("Up" . outline-up-heading)))
 138
 139 (defvar outline-mode-map nil "")
 140
 141 (if outline-mode-map
 142     nil
 143   (setq outline-mode-map (nconc (make-sparse-keymap) text-mode-map))
 144   (define-key outline-mode-map "\C-c" outline-mode-prefix-map)
 145   (define-key outline-mode-map [menu-bar] outline-mode-menu-bar-map))
 146
 147 (defvar outline-font-lock-keywords
 148   '(;;
 149     ;; Highlight headings according to the level.
 150     (eval . (list (concat "^" outline-regexp ".+")
 151                   0 '(or (cdr (assq (outline-font-lock-level)
 152                                     '((1 . font-lock-function-name-face)
 153                                       (2 . font-lock-variable-name-face)
 154                                       (3 . font-lock-keyword-face)
 155                                       (4 . font-lock-builtin-face)
 156                                       (5 . font-lock-comment-face)
 157                                       (6 . font-lock-constant-face)
 158                                       (7 . font-lock-type-face)
 159                                       (8 . font-lock-string-face))))
 160                          font-lock-warning-face)
 161                   nil t)))
 162   "Additional expressions to highlight in Outline mode.")
 163
 164 (defun outline-font-lock-level ()
 165   (let ((count 1))
 166     (save-excursion
 167       (outline-back-to-heading t)
 168       (condition-case nil
 169           (while (not (bobp))
 170             (outline-up-heading-all 1)
 171             (setq count (1+ count)))
 172         (error)))
 173     count))
 174
 175 (defvar outline-view-change-hook nil
 176   "Normal hook to be run after outline visibility changes.")
 177
 178 ;;;###autoload
 179 (define-derived-mode outline-mode text-mode "Outline"
 180   "Set major mode for editing outlines with selective display.
 181 Headings are lines which start with asterisks: one for major headings,
 182 two for subheadings, etc.  Lines not starting with asterisks are body lines.
 183
 184 Body text or subheadings under a heading can be made temporarily
 185 invisible, or visible again.  Invisible lines are attached to the end
 186 of the heading, so they move with it, if the line is killed and yanked
 187 back.  A heading with text hidden under it is marked with an ellipsis (...).
 188
 189 Commands:\\<outline-mode-map>
 190 \\[outline-next-visible-heading]   outline-next-visible-heading      move by visible headings
 191 \\[outline-previous-visible-heading]   outline-previous-visible-heading
 192 \\[outline-forward-same-level]   outline-forward-same-level        similar but skip subheadings
 193 \\[outline-backward-same-level]   outline-backward-same-level
 194 \\[outline-up-heading]   outline-up-heading                 move from subheading to heading
 195
 196 \\[hide-body]   make all text invisible (not headings).
 197 \\[show-all]    make everything in buffer visible.
 198
 199 The remaining commands are used when point is on a heading line.
 200 They apply to some of the body or subheadings of that heading.
 201 \\[hide-subtree]   hide-subtree make body and subheadings invisible.
 202 \\[show-subtree]   show-subtree make body and subheadings visible.
 203 \\[show-children]   show-children       make direct subheadings visible.
 204                  No effect on body, or subheadings 2 or more levels down.
 205                  With arg N, affects subheadings N levels down.
 206 \\[hide-entry]     make immediately following body invisible.
 207 \\[show-entry]     make it visible.
 208 \\[hide-leaves]    make body under heading and under its subheadings invisible.
 209                      The subheadings remain visible.
 210 \\[show-branches]  make all subheadings at all levels visible.
 211
 212 The variable `outline-regexp' can be changed to control what is a heading.
 213 A line is a heading if `outline-regexp' matches something at the
 214 beginning of the line.  The longer the match, the deeper the level.
 215
 216 Turning on outline mode calls the value of `text-mode-hook' and then of
 217 `outline-mode-hook', if they are non-nil."
 218   (make-local-variable 'line-move-ignore-invisible)
 219   (setq line-move-ignore-invisible t)
 220   ;; Cause use of ellipses for invisible text.
 221   (add-to-invisibility-spec '(outline . t))
 222   (set (make-local-variable 'paragraph-start)
 223        (concat paragraph-start "\\|\\(" outline-regexp "\\)"))
 224   ;; Inhibit auto-filling of header lines.
 225   (set (make-local-variable 'auto-fill-inhibit-regexp) outline-regexp)
 226   (set (make-local-variable 'paragraph-separate)
 227        (concat paragraph-separate "\\|\\(" outline-regexp "\\)"))
 228   (set (make-local-variable 'font-lock-defaults)
 229        '(outline-font-lock-keywords t))
 230   (setq imenu-generic-expression
 231         (list (list nil (concat outline-regexp ".*$") 0)))
 232   (add-hook 'change-major-mode-hook 'show-all nil t))
 233
 234 (defcustom outline-minor-mode-prefix "\C-c@"
 235   "*Prefix key to use for Outline commands in Outline minor mode.
 236 The value of this variable is checked as part of loading Outline mode.
 237 After that, changing the prefix key requires manipulating keymaps."
 238   :type 'string
 239   :group 'outlines)
 240
 241 ;;;###autoload
 242 (define-minor-mode outline-minor-mode
 243   "Toggle Outline minor mode.
 244 With arg, turn Outline minor mode on if arg is positive, off otherwise.
 245 See the command `outline-mode' for more information on this mode."
 246   nil " Outl" (list (cons [menu-bar] outline-mode-menu-bar-map)
 247                     (cons outline-minor-mode-prefix outline-mode-prefix-map))
 248   (if outline-minor-mode
 249       (progn
 250         ;; Turn off this mode if we change major modes.
 251         (add-hook 'change-major-mode-hook
 252                   (lambda () (outline-minor-mode -1))
 253                   nil t)
 254         (set (make-local-variable 'line-move-ignore-invisible) t)
 255         ;; Cause use of ellipses for invisible text.
 256         (add-to-invisibility-spec '(outline . t)))
 257     (setq line-move-ignore-invisible nil)
 258     ;; Cause use of ellipses for invisible text.
 259     (remove-from-invisibility-spec '(outline . t)))
 260   ;; When turning off outline mode, get rid of any outline hiding.
 261   (or outline-minor-mode
 262       (show-all)))
 263 \f
 264 (defcustom outline-level 'outline-level
 265   "*Function of no args to compute a header's nesting level in an outline.
 266 It can assume point is at the beginning of a header line."
 267   :type 'function
 268   :group 'outlines)
 269
 270 ;; This used to count columns rather than characters, but that made ^L
 271 ;; appear to be at level 2 instead of 1.  Columns would be better for
 272 ;; tab handling, but the default regexp doesn't use tabs, and anyone
 273 ;; who changes the regexp can also redefine the outline-level variable
 274 ;; as appropriate.
 275 (defun outline-level ()
 276   "Return the depth to which a statement is nested in the outline.
 277 Point must be at the beginning of a header line.  This is actually
 278 the number of characters that `outline-regexp' matches."
 279   (save-excursion
 280     (looking-at outline-regexp)
 281     (- (match-end 0) (match-beginning 0))))
 282
 283 (defun outline-next-preface ()
 284   "Skip forward to just before the next heading line.
 285 If there's no following heading line, stop before the newline
 286 at the end of the buffer."
 287   (if (re-search-forward (concat "\n\\(" outline-regexp "\\)")
 288                          nil 'move)
 289       (goto-char (match-beginning 0)))
 290   (if (and (bolp) (not (bobp)))
 291       (forward-char -1)))
 292
 293 (defun outline-next-heading ()
 294   "Move to the next (possibly invisible) heading line."
 295   (interactive)
 296   (if (re-search-forward (concat "\n\\(" outline-regexp "\\)")
 297                          nil 'move)
 298       (goto-char (1+ (match-beginning 0)))))
 299
 300 (defun outline-previous-heading ()
 301   "Move to the previous (possibly invisible) heading line."
 302   (interactive)
 303   (re-search-backward (concat "^\\(" outline-regexp "\\)")
 304                       nil 'move))
 305
 306 (defsubst outline-visible ()
 307   "Non-nil if the character after point is visible."
 308   (not (get-char-property (point) 'invisible)))
 309
 310 (defun outline-back-to-heading (&optional invisible-ok)
 311   "Move to previous heading line, or beg of this line if it's a heading.
 312 Only visible heading lines are considered, unless INVISIBLE-OK is non-nil."
 313   (beginning-of-line)
 314   (or (outline-on-heading-p invisible-ok)
 315       (let (found)
 316         (save-excursion
 317           (while (not found)
 318             (or (re-search-backward (concat "^\\(" outline-regexp "\\)")
 319                                     nil t)
 320                 (error "before first heading"))
 321             (setq found (and (or invisible-ok (outline-visible)) (point)))))
 322         (goto-char found)
 323         found)))
 324
 325 (defun outline-on-heading-p (&optional invisible-ok)
 326   "Return t if point is on a (visible) heading line.
 327 If INVISIBLE-OK is non-nil, an invisible heading line is ok too."
 328   (save-excursion
 329     (beginning-of-line)
 330     (and (bolp) (or invisible-ok (outline-visible))
 331          (looking-at outline-regexp))))
 332
 333 (defun outline-end-of-heading ()
 334   (if (re-search-forward outline-heading-end-regexp nil 'move)
 335       (forward-char -1)))
 336
 337 (defun outline-next-visible-heading (arg)
 338   "Move to the next visible heading line.
 339 With argument, repeats or can move backward if negative.
 340 A heading line is one that starts with a `*' (or that
 341 `outline-regexp' matches)."
 342   (interactive "p")
 343   (if (< arg 0)
 344       (beginning-of-line)
 345     (end-of-line))
 346   (while (and (not (bobp)) (< arg 0))
 347     (while (and (not (bobp))
 348                 (re-search-backward (concat "^\\(" outline-regexp "\\)")
 349                                     nil 'move)
 350                 (not (outline-visible))))
 351     (setq arg (1+ arg)))
 352   (while (and (not (eobp)) (> arg 0))
 353     (while (and (not (eobp))
 354                 (re-search-forward (concat "^\\(" outline-regexp "\\)")
 355                                    nil 'move)
 356                 (not (outline-visible))))
 357     (setq arg (1- arg)))
 358   (beginning-of-line))
 359
 360 (defun outline-previous-visible-heading (arg)
 361   "Move to the previous heading line.
 362 With argument, repeats or can move forward if negative.
 363 A heading line is one that starts with a `*' (or that
 364 `outline-regexp' matches)."
 365   (interactive "p")
 366   (outline-next-visible-heading (- arg)))
 367
 368 (defun outline-mark-subtree ()
 369   "Mark the current subtree in an outlined document.
 370 This puts point at the start of the current subtree, and mark at the end."
 371   (interactive)
 372   (let ((beg))
 373     (if (outline-on-heading-p)
 374         ;; we are already looking at a heading
 375         (beginning-of-line)
 376       ;; else go back to previous heading
 377       (outline-previous-visible-heading 1))
 378     (setq beg (point))
 379     (outline-end-of-subtree)
 380     (push-mark (point))
 381     (goto-char beg)))
 382 \f
 383 (defun outline-flag-region (from to flag)
 384   "Hides or shows lines from FROM to TO, according to FLAG.
 385 If FLAG is nil then text is shown, while if FLAG is t the text is hidden."
 386   (save-excursion
 387     (goto-char from)
 388     (end-of-line)
 389     (outline-discard-overlays (point) to 'outline)
 390     (if flag
 391         (let ((o (make-overlay (point) to)))
 392           (overlay-put o 'invisible 'outline)
 393           (overlay-put o 'isearch-open-invisible
 394                        'outline-isearch-open-invisible))))
 395   (run-hooks 'outline-view-change-hook))
 396
 397
 398 ;; Function to be set as an outline-isearch-open-invisible' property
 399 ;; to the overlay that makes the outline invisible (see
 400 ;; `outline-flag-region').
 401 (defun outline-isearch-open-invisible (overlay)
 402   ;; We rely on the fact that isearch places point one the matched text.
 403   (show-entry))
 404
 405
 406 ;; Exclude from the region BEG ... END all overlays
 407 ;; which have PROP as the value of the `invisible' property.
 408 ;; Exclude them by shrinking them to exclude BEG ... END,
 409 ;; or even by splitting them if necessary.
 410 ;; Overlays without such an `invisible' property are not touched.
 411 (defun outline-discard-overlays (beg end prop)
 412   (if (< end beg)
 413       (setq beg (prog1 end (setq end beg))))
 414   (save-excursion
 415     (dolist (o (overlays-in beg end))
 416       (if (eq (overlay-get o 'invisible) prop)
 417           ;; Either push this overlay outside beg...end
 418           ;; or split it to exclude beg...end
 419           ;; or delete it entirely (if it is contained in beg...end).
 420           (if (< (overlay-start o) beg)
 421               (if (> (overlay-end o) end)
 422                   (progn
 423                     (move-overlay (outline-copy-overlay o)
 424                                   (overlay-start o) beg)
 425                     (move-overlay o end (overlay-end o)))
 426                 (move-overlay o (overlay-start o) beg))
 427             (if (> (overlay-end o) end)
 428                 (move-overlay o end (overlay-end o))
 429               (delete-overlay o))))))))
 430
 431 ;; Make a copy of overlay O, with the same beginning, end and properties.
 432 (defun outline-copy-overlay (o)
 433   (let ((o1 (make-overlay (overlay-start o) (overlay-end o)
 434                           (overlay-buffer o)))
 435         (props (overlay-properties o)))
 436     (while props
 437       (overlay-put o1 (car props) (nth 1 props))
 438       (setq props (cdr (cdr props))))
 439     o1))
 440 \f
 441 (defun hide-entry ()
 442   "Hide the body directly following this heading."
 443   (interactive)
 444   (outline-back-to-heading)
 445   (outline-end-of-heading)
 446   (save-excursion
 447    (outline-flag-region (point) (progn (outline-next-preface) (point)) t)))
 448
 449 (defun show-entry ()
 450   "Show the body directly following this heading.
 451 Show the heading too, if it is currently invisible."
 452   (interactive)
 453   (save-excursion
 454     (outline-back-to-heading t)
 455     (outline-flag-region (1- (point))
 456                          (progn (outline-next-preface) (point)) nil)))
 457
 458 (defun hide-body ()
 459   "Hide all of buffer except headings."
 460   (interactive)
 461   (hide-region-body (point-min) (point-max)))
 462
 463 (defun hide-region-body (start end)
 464   "Hide all body lines in the region, but not headings."
 465   ;; Nullify the hook to avoid repeated calls to `outline-flag-region'
 466   ;; wasting lots of time running `lazy-lock-fontify-after-outline'
 467   ;; and run the hook finally.
 468   (let (outline-view-change-hook)
 469     (save-excursion
 470       (save-restriction
 471         (narrow-to-region start end)
 472         (goto-char (point-min))
 473         (if (outline-on-heading-p)
 474             (outline-end-of-heading))
 475         (while (not (eobp))
 476           (outline-flag-region (point)
 477                                (progn (outline-next-preface) (point)) t)
 478           (if (not (eobp))
 479               (progn
 480                 (forward-char
 481                  (if (looking-at "\n\n")
 482                      2 1))
 483                 (outline-end-of-heading)))))))
 484   (run-hooks 'outline-view-change-hook))
 485
 486 (defun show-all ()
 487   "Show all of the text in the buffer."
 488   (interactive)
 489   (outline-flag-region (point-min) (point-max) nil))
 490
 491 (defun hide-subtree ()
 492   "Hide everything after this heading at deeper levels."
 493   (interactive)
 494   (outline-flag-subtree t))
 495
 496 (defun hide-leaves ()
 497   "Hide all body after this heading at deeper levels."
 498   (interactive)
 499   (outline-back-to-heading)
 500   (outline-end-of-heading)
 501   (hide-region-body (point) (progn (outline-end-of-subtree) (point))))
 502
 503 (defun show-subtree ()
 504   "Show everything after this heading at deeper levels."
 505   (interactive)
 506   (outline-flag-subtree nil))
 507
 508 (defun hide-sublevels (levels)
 509   "Hide everything but the top LEVELS levels of headers, in whole buffer."
 510   (interactive "p")
 511   (if (< levels 1)
 512       (error "Must keep at least one level of headers"))
 513   (setq levels (1- levels))
 514   (let (outline-view-change-hook)
 515     (save-excursion
 516       (goto-char (point-min))
 517       ;; Keep advancing to the next top-level heading.
 518       (while (or (and (bobp) (outline-on-heading-p))
 519                  (outline-next-heading))
 520         (let ((end (save-excursion (outline-end-of-subtree) (point))))
 521           ;; Hide everything under that.
 522           (outline-flag-region (point) end t)
 523           ;; Show the first LEVELS levels under that.
 524           (if (> levels 0)
 525               (show-children levels))
 526           ;; Move to the next, since we already found it.
 527           (goto-char end)))))
 528   (run-hooks 'outline-view-change-hook))
 529
 530 (defun hide-other ()
 531   "Hide everything except current body and parent and top-level headings."
 532   (interactive)
 533   (hide-sublevels 1)
 534   (let (outline-view-change-hook)
 535     (save-excursion
 536       (outline-back-to-heading t)
 537       (show-entry)
 538       (while (condition-case nil (progn (outline-up-heading 1) t)
 539                (error nil))
 540         (outline-flag-region (1- (point))
 541                              (save-excursion (forward-line 1) (point))
 542                              nil))))
 543   (run-hooks 'outline-view-change-hook))
 544
 545 (defun outline-flag-subtree (flag)
 546   (save-excursion
 547     (outline-back-to-heading)
 548     (outline-end-of-heading)
 549     (outline-flag-region (point)
 550                           (progn (outline-end-of-subtree) (point))
 551                           flag)))
 552
 553 (defun outline-end-of-subtree ()
 554   (outline-back-to-heading)
 555   (let ((opoint (point))
 556         (first t)
 557         (level (funcall outline-level)))
 558     (while (and (not (eobp))
 559                 (or first (> (funcall outline-level) level)))
 560       (setq first nil)
 561       (outline-next-heading))
 562     (if (bolp)
 563         (progn
 564           ;; Go to end of line before heading
 565           (forward-char -1)
 566           (if (bolp)
 567               ;; leave blank line before heading
 568               (forward-char -1))))))
 569 \f
 570 (defun show-branches ()
 571   "Show all subheadings of this heading, but not their bodies."
 572   (interactive)
 573   (show-children 1000))
 574
 575 (defun show-children (&optional level)
 576   "Show all direct subheadings of this heading.
 577 Prefix arg LEVEL is how many levels below the current level should be shown.
 578 Default is enough to cause the following heading to appear."
 579   (interactive "P")
 580   (setq level
 581         (if level (prefix-numeric-value level)
 582           (save-excursion
 583             (outline-back-to-heading)
 584             (let ((start-level (funcall outline-level)))
 585               (outline-next-heading)
 586               (if (eobp)
 587                   1
 588                 (max 1 (- (funcall outline-level) start-level)))))))
 589   (let (outline-view-change-hook)
 590     (save-excursion
 591       (save-restriction
 592         (outline-back-to-heading)
 593         (setq level (+ level (funcall outline-level)))
 594         (narrow-to-region (point)
 595                           (progn (outline-end-of-subtree)
 596                                  (if (eobp) (point-max) (1+ (point)))))
 597         (goto-char (point-min))
 598         (while (and (not (eobp))
 599                     (progn
 600                       (outline-next-heading)
 601                       (not (eobp))))
 602           (if (<= (funcall outline-level) level)
 603               (save-excursion
 604                 (outline-flag-region (save-excursion
 605                                        (forward-char -1)
 606                                        (if (bolp)
 607                                            (forward-char -1))
 608                                        (point))
 609                                      (progn (outline-end-of-heading) (point))
 610                                      nil)))))))
 611   (run-hooks 'outline-view-change-hook))
 612 \f
 613 (defun outline-up-heading-all (arg)
 614   "Move to the heading line of which the present line is a subheading.
 615 This function considers both visible and invisible heading lines.
 616 With argument, move up ARG levels."
 617   (outline-back-to-heading t)
 618   (if (eq (funcall outline-level) 1)
 619       (error "Already at top level of the outline"))
 620   (while (and (> (funcall outline-level) 1)
 621               (> arg 0)
 622               (not (bobp)))
 623     (let ((present-level (funcall outline-level)))
 624       (while (and (not (< (funcall outline-level) present-level))
 625                   (not (bobp)))
 626         (outline-previous-heading))
 627       (setq arg (- arg 1)))))
 628
 629 (defun outline-up-heading (arg)
 630   "Move to the visible heading line of which the present line is a subheading.
 631 With argument, move up ARG levels."
 632   (interactive "p")
 633   (outline-back-to-heading)
 634   (if (eq (funcall outline-level) 1)
 635       (error "Already at top level of the outline"))
 636   (while (and (> (funcall outline-level) 1)
 637               (> arg 0)
 638               (not (bobp)))
 639     (let ((present-level (funcall outline-level)))
 640       (while (and (not (< (funcall outline-level) present-level))
 641                   (not (bobp)))
 642         (outline-previous-visible-heading 1))
 643       (setq arg (- arg 1)))))
 644
 645 (defun outline-forward-same-level (arg)
 646   "Move forward to the ARG'th subheading at same level as this one.
 647 Stop at the first and last subheadings of a superior heading."
 648   (interactive "p")
 649   (outline-back-to-heading)
 650   (while (> arg 0)
 651     (let ((point-to-move-to (save-excursion
 652                               (outline-get-next-sibling))))
 653       (if point-to-move-to
 654           (progn
 655             (goto-char point-to-move-to)
 656             (setq arg (1- arg)))
 657         (progn
 658           (setq arg 0)
 659           (error "No following same-level heading"))))))
 660
 661 (defun outline-get-next-sibling ()
 662   "Move to next heading of the same level, and return point or nil if none."
 663   (let ((level (funcall outline-level)))
 664     (outline-next-visible-heading 1)
 665     (while (and (> (funcall outline-level) level)
 666                 (not (eobp)))
 667       (outline-next-visible-heading 1))
 668     (if (< (funcall outline-level) level)
 669         nil
 670       (point))))
 671
 672 (defun outline-backward-same-level (arg)
 673   "Move backward to the ARG'th subheading at same level as this one.
 674 Stop at the first and last subheadings of a superior heading."
 675   (interactive "p")
 676   (outline-back-to-heading)
 677   (while (> arg 0)
 678     (let ((point-to-move-to (save-excursion
 679                               (outline-get-last-sibling))))
 680       (if point-to-move-to
 681           (progn
 682             (goto-char point-to-move-to)
 683             (setq arg (1- arg)))
 684         (progn
 685           (setq arg 0)
 686           (error "No previous same-level heading"))))))
 687
 688 (defun outline-get-last-sibling ()
 689   "Move to previous heading of the same level, and return point or nil if none."
 690   (let ((level (funcall outline-level)))
 691     (outline-previous-visible-heading 1)
 692     (while (and (> (funcall outline-level) level)
 693                 (not (bobp)))
 694       (outline-previous-visible-heading 1))
 695     (if (< (funcall outline-level) level)
 696         nil
 697         (point))))
 698 \f
 699 (defun outline-headers-as-kill (beg end)
 700   "Save the visible outline headers in region at the start of the kill ring.
 701
 702 Text shown between the headers isn't copied.  Two newlines are
 703 inserted between saved headers.  Yanking the result may be a
 704 convenient way to make a table of contents of the buffer."
 705   (interactive "r")
 706   (save-excursion
 707     (save-restriction
 708       (narrow-to-region beg end)
 709       (goto-char (point-min))
 710       (let ((buffer (current-buffer))
 711             start end)
 712         (with-temp-buffer
 713           (with-current-buffer buffer
 714             ;; Boundary condition: starting on heading:
 715             (when (outline-on-heading-p)
 716               (outline-back-to-heading)
 717               (setq start (point)
 718                     end (progn (outline-end-of-heading)
 719                                (point)))
 720               (insert-buffer-substring buffer start end)
 721               (insert "\n\n")))
 722           (let ((temp-buffer (current-buffer)))
 723             (with-current-buffer buffer
 724               (while (outline-next-heading)
 725                 (when (outline-visible)
 726                   (setq start (point)
 727                         end (progn (outline-end-of-heading) (point)))
 728                   (with-current-buffer temp-buffer
 729                     (insert-buffer-substring buffer start end)
 730                     (insert "\n\n"))))))
 731           (kill-new (buffer-string)))))))
 732
 733 (provide 'outline)
 734 (provide 'noutline)
 735
 736 ;;; outline.el ends here