lisp/textmodes/paragraphs.el

   1 ;;; paragraphs.el --- paragraph and sentence parsing.
   2
   3 ;; Copyright (C) 1985, 86, 87, 91, 94, 95 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: wp
   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 paragraph-oriented commands documented in the
  28 ;; Emacs manual.
  29
  30 ;;; Code:
  31
  32 (defvar use-hard-newlines nil
  33     "Non-nil means to distinguish hard and soft newlines.
  34 When this is non-nil, the functions `newline' and `open-line' add the
  35 text-property `hard' to newlines that they insert.  Also, a line is
  36 only considered as a candidate to match `paragraph-start' or
  37 `paragraph-separate' if it follows a hard newline.  Newlines not
  38 marked hard are called \"soft\", and are always internal to
  39 paragraphs.  The fill functions always insert soft newlines.
  40
  41 Each buffer has its own value of this variable.")
  42 (make-variable-buffer-local 'use-hard-newlines)
  43
  44 (defconst paragraph-start "[ \t\n\f]" "\
  45 *Regexp for beginning of a line that starts OR separates paragraphs.
  46 This regexp should match lines that separate paragraphs
  47 and should also match lines that start a paragraph
  48 \(and are part of that paragraph).
  49
  50 This is matched against the text at the left margin, which is not necessarily
  51 the beginning of the line, so it should never use \"^\" as an anchor.  This
  52 ensures that the paragraph functions will work equally well within a region
  53 of text indented by a margin setting.
  54
  55 The variable `paragraph-separate' specifies how to distinguish
  56 lines that start paragraphs from lines that separate them.
  57
  58 If the variable `use-hard-newlines' is nonnil, then only lines following a
  59 hard newline are considered to match.")
  60
  61 ;; paragraph-start requires a hard newline, but paragraph-separate does not:
  62 ;; It is assumed that paragraph-separate is distinctive enough to be believed
  63 ;; whenever it occurs, while it is reasonable to set paragraph-start to
  64 ;; something very minimal, even including "." (which makes every hard newline
  65 ;; start a new paragraph).
  66
  67 (defconst paragraph-separate "[ \t\f]*$" "\
  68 *Regexp for beginning of a line that separates paragraphs.
  69 If you change this, you may have to change paragraph-start also.
  70
  71 This is matched against the text at the left margin, which is not necessarily
  72 the beginning of the line, so it should not use \"^\" as an anchor.  This
  73 ensures that the paragraph functions will work equally within a region of
  74 text indented by a margin setting.")
  75
  76 (defconst sentence-end (purecopy "[.?!][]\"')}]*\\($\\| $\\|\t\\|  \\)[ \t\n]*") "\
  77 *Regexp describing the end of a sentence.
  78 All paragraph boundaries also end sentences, regardless.
  79
  80 In order to be recognized as the end of a sentence, the ending period,
  81 question mark, or exclamation point must be followed by two spaces,
  82 unless it's inside some sort of quotes or parenthesis.")
  83
  84 (defconst page-delimiter "^\014" "\
  85 *Regexp describing line-beginnings that separate pages.")
  86
  87 (defvar paragraph-ignore-fill-prefix nil "\
  88 Non-nil means the paragraph commands are not affected by `fill-prefix'.
  89 This is desirable in modes where blank lines are the paragraph delimiters.")
  90
  91 (defun forward-paragraph (&optional arg)
  92   "Move forward to end of paragraph.
  93 With arg N, do it N times; negative arg -N means move backward N paragraphs.
  94
  95 A line which `paragraph-start' matches either separates paragraphs
  96 \(if `paragraph-separate' matches it also) or is the first line of a paragraph.
  97 A paragraph end is the beginning of a line which is not part of the paragraph
  98 to which the end of the previous line belongs, or the end of the buffer."
  99   (interactive "p")
 100   (or arg (setq arg 1))
 101   (let* ((fill-prefix-regexp
 102           (and fill-prefix (not (equal fill-prefix ""))
 103                (not paragraph-ignore-fill-prefix)
 104                (regexp-quote fill-prefix)))
 105          ;; Remove ^ from paragraph-start and paragraph-sep if they are there.
 106          ;; These regexps shouldn't be anchored, because we look for them
 107          ;; starting at the left-margin.  This allows paragraph commands to
 108          ;; work normally with indented text.
 109          ;; This hack will not find problem cases like "whatever\\|^something".
 110          (paragraph-start (if (and (not (equal "" paragraph-start))
 111                                    (equal ?^ (aref paragraph-start 0)))
 112                               (substring paragraph-start 1)
 113                             paragraph-start))
 114          (paragraph-separate (if (and (not (equal "" paragraph-start))
 115                                       (equal ?^ (aref paragraph-separate 0)))
 116                               (substring paragraph-separate 1)
 117                             paragraph-separate))
 118          (paragraph-separate
 119           (if fill-prefix-regexp
 120               (concat paragraph-separate "\\|"
 121                       fill-prefix-regexp "[ \t]*$")
 122             paragraph-separate))
 123          ;; This is used for searching.
 124          (sp-paragraph-start (concat "^[ \t]*\\(" paragraph-start "\\)"))
 125          start)
 126     (while (and (< arg 0) (not (bobp)))
 127       (if (and (not (looking-at paragraph-separate))
 128                (re-search-backward "^\n" (max (1- (point)) (point-min)) t)
 129                (looking-at paragraph-separate))
 130           nil
 131         (setq start (point))
 132         ;; Move back over paragraph-separating lines.
 133         (forward-char -1) (beginning-of-line)
 134         (while (and (not (bobp))
 135                     (progn (move-to-left-margin)
 136                            (looking-at paragraph-separate)))
 137           (forward-line -1))
 138         (if (bobp)
 139             nil
 140           ;; Go to end of the previous (non-separating) line.
 141           (end-of-line)
 142           ;; Search back for line that starts or separates paragraphs.
 143           (if (if fill-prefix-regexp
 144                   ;; There is a fill prefix; it overrides paragraph-start.
 145                   (let (multiple-lines)
 146                     (while (and (progn (beginning-of-line) (not (bobp)))
 147                                 (progn (move-to-left-margin)
 148                                        (not (looking-at paragraph-separate)))
 149                                 (looking-at fill-prefix-regexp))
 150                       (if (not (= (point) start))
 151                           (setq multiple-lines t))
 152                       (forward-line -1))
 153                     (move-to-left-margin)
 154                     ;; Don't move back over a line before the paragraph
 155                     ;; which doesn't start with fill-prefix
 156                     ;; unless that is the only line we've moved over.
 157                     (and (not (looking-at fill-prefix-regexp))
 158                          multiple-lines
 159                          (forward-line 1))
 160                     (not (bobp)))
 161                 (while (and (re-search-backward sp-paragraph-start nil 1)
 162                             ;; Found a candidate, but need to check if it is a
 163                             ;; REAL paragraph-start.
 164                             (not (bobp))
 165                             (progn (setq start (point))
 166                                    (move-to-left-margin)
 167                                    (not (looking-at paragraph-separate)))
 168                             (or (not (looking-at paragraph-start))
 169                                 (and use-hard-newlines
 170                                      (not (get-text-property (1- start)
 171                                                              'hard)))))
 172                   (goto-char start))
 173                 (> (point) (point-min)))
 174               ;; Found one.
 175               (progn
 176                 ;; Move forward over paragraph separators.
 177                 ;; We know this cannot reach the place we started
 178                 ;; because we know we moved back over a non-separator.
 179                 (while (and (not (eobp))
 180                             (progn (move-to-left-margin)
 181                                    (looking-at paragraph-separate)))
 182                   (forward-line 1))
 183                 ;; If line before paragraph is just margin, back up to there.
 184                 (end-of-line 0)
 185                 (if (> (current-column) (current-left-margin))
 186                     (forward-char 1)
 187                   (skip-chars-backward " \t")
 188                   (if (not (bolp))
 189                       (forward-line 1))))
 190             ;; No starter or separator line => use buffer beg.
 191             (goto-char (point-min)))))
 192       (setq arg (1+ arg)))
 193     (while (and (> arg 0) (not (eobp)))
 194       (while (prog1 (and (not (eobp))
 195                          (progn (move-to-left-margin) (not (eobp)))
 196                          (looking-at paragraph-separate))
 197                (forward-line 1)))
 198       (if fill-prefix-regexp
 199           ;; There is a fill prefix; it overrides paragraph-start.
 200           (while (and (not (eobp))
 201                       (progn (move-to-left-margin) (not (eobp)))
 202                       (not (looking-at paragraph-separate))
 203                       (looking-at fill-prefix-regexp))
 204             (forward-line 1))
 205         (while (and (re-search-forward sp-paragraph-start nil 1)
 206                     (progn (setq start (match-beginning 0))
 207                            (goto-char start)
 208                            (not (eobp)))
 209                     (progn (move-to-left-margin)
 210                            (not (looking-at paragraph-separate)))
 211                     (or (not (looking-at paragraph-start))
 212                         (and use-hard-newlines
 213                              (not (get-text-property (1- start) 'hard)))))
 214           (forward-char 1))
 215         (if (< (point) (point-max))
 216             (goto-char start)))
 217       (setq arg (1- arg)))))
 218
 219 (defun backward-paragraph (&optional arg)
 220   "Move backward to start of paragraph.
 221 With arg N, do it N times; negative arg -N means move forward N paragraphs.
 222
 223 A paragraph start is the beginning of a line which is a
 224 `first-line-of-paragraph' or which is ordinary text and follows a
 225 paragraph-separating line; except: if the first real line of a
 226 paragraph is preceded by a blank line, the paragraph starts at that
 227 blank line.
 228
 229 See `forward-paragraph' for more information."
 230   (interactive "p")
 231   (or arg (setq arg 1))
 232   (forward-paragraph (- arg)))
 233
 234 (defun mark-paragraph ()
 235   "Put point at beginning of this paragraph, mark at end.
 236 The paragraph marked is the one that contains point or follows point."
 237   (interactive)
 238   (forward-paragraph 1)
 239   (push-mark nil t t)
 240   (backward-paragraph 1))
 241
 242 (defun kill-paragraph (arg)
 243   "Kill forward to end of paragraph.
 244 With arg N, kill forward to Nth end of paragraph;
 245 negative arg -N means kill backward to Nth start of paragraph."
 246   (interactive "p")
 247   (kill-region (point) (progn (forward-paragraph arg) (point))))
 248
 249 (defun backward-kill-paragraph (arg)
 250   "Kill back to start of paragraph.
 251 With arg N, kill back to Nth start of paragraph;
 252 negative arg -N means kill forward to Nth end of paragraph."
 253   (interactive "p")
 254   (kill-region (point) (progn (backward-paragraph arg) (point))))
 255
 256 (defun transpose-paragraphs (arg)
 257   "Interchange this (or next) paragraph with previous one."
 258   (interactive "*p")
 259   (transpose-subr 'forward-paragraph arg))
 260
 261 (defun start-of-paragraph-text ()
 262   (let ((opoint (point)) npoint)
 263     (forward-paragraph -1)
 264     (setq npoint (point))
 265     (skip-chars-forward " \t\n")
 266     ;; If the range of blank lines found spans the original start point,
 267     ;; try again from the beginning of it.
 268     ;; Must be careful to avoid infinite loop
 269     ;; when following a single return at start of buffer.
 270     (if (and (>= (point) opoint) (< npoint opoint))
 271         (progn
 272           (goto-char npoint)
 273           (if (> npoint (point-min))
 274               (start-of-paragraph-text))))))
 275
 276 (defun end-of-paragraph-text ()
 277   (let ((opoint (point)))
 278     (forward-paragraph 1)
 279     (if (eq (preceding-char) ?\n) (forward-char -1))
 280     (if (<= (point) opoint)
 281         (progn
 282           (forward-char 1)
 283           (if (< (point) (point-max))
 284               (end-of-paragraph-text))))))
 285
 286 (defun forward-sentence (&optional arg)
 287   "Move forward to next `sentence-end'.  With argument, repeat.
 288 With negative argument, move backward repeatedly to `sentence-beginning'.
 289
 290 The variable `sentence-end' is a regular expression that matches ends of
 291 sentences.  Also, every paragraph boundary terminates sentences as well."
 292   (interactive "p")
 293   (or arg (setq arg 1))
 294   (while (< arg 0)
 295     (let ((par-beg (save-excursion (start-of-paragraph-text) (point))))
 296       (if (re-search-backward (concat sentence-end "[^ \t\n]") par-beg t)
 297           (goto-char (1- (match-end 0)))
 298         (goto-char par-beg)))
 299     (setq arg (1+ arg)))
 300   (while (> arg 0)
 301     (let ((par-end (save-excursion (end-of-paragraph-text) (point))))
 302       (if (re-search-forward sentence-end par-end t)
 303           (skip-chars-backward " \t\n")
 304         (goto-char par-end)))
 305     (setq arg (1- arg))))
 306
 307 (defun backward-sentence (&optional arg)
 308   "Move backward to start of sentence.  With arg, do it arg times.
 309 See `forward-sentence' for more information."
 310   (interactive "p")
 311   (or arg (setq arg 1))
 312   (forward-sentence (- arg)))
 313
 314 (defun kill-sentence (&optional arg)
 315   "Kill from point to end of sentence.
 316 With arg, repeat; negative arg -N means kill back to Nth start of sentence."
 317   (interactive "p")
 318   (kill-region (point) (progn (forward-sentence arg) (point))))
 319
 320 (defun backward-kill-sentence (&optional arg)
 321   "Kill back from point to start of sentence.
 322 With arg, repeat, or kill forward to Nth end of sentence if negative arg -N."
 323   (interactive "p")
 324   (kill-region (point) (progn (backward-sentence arg) (point))))
 325
 326 (defun mark-end-of-sentence (arg)
 327   "Put mark at end of sentence.  Arg works as in `forward-sentence'."
 328   (interactive "p")
 329   (push-mark
 330     (save-excursion
 331       (forward-sentence arg)
 332       (point))
 333     nil t))
 334
 335 (defun transpose-sentences (arg)
 336   "Interchange this (next) and previous sentence."
 337   (interactive "*p")
 338   (transpose-subr 'forward-sentence arg))
 339
 340 ;;; paragraphs.el ends here