code.delx.au - gnu-emacs/blob - lisp/international/kinsoku.el

   1 ;;; kinsoku.el --- `Kinsoku' processing functions.
   2
   3 ;; Copyright (C) 1995 Free Software Foundation, Inc.
   4 ;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
   5
   6 ;; Keywords: kinsoku
   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 ;; `Kinsoku' processing is to prohibit specific characters to be
  28 ;; placed at beginning of line or at end of line.  Characters not to
  29 ;; be placed at beginning and end of line have character category `>'
  30 ;; and `<' respectively.   This restriction is dissolved by making a
  31 ;; line longer or shorter.
  32 ;;
  33 ;; `Kinsoku' is a Japanese word which originally means ordering to
  34 ;; stay in one place, and is used for the text processing described
  35 ;; above in the context of text formatting.
  36
  37 ;;; Code:
  38
  39 (defvar kinsoku-limit 4
  40   "How many more columns we can make lines longer by `kinsoku' processing.
  41 The value 0 means there's no limitation.")
  42
  43 ;; Setting character category `>' for characters which should not be
  44 ;; placed at beginning of line.
  45 (let* ((kinsoku-bol
  46         (concat
  47          ;; ASCII
  48          "!)-_~}]:;',.?"
  49          ;; Japanese JISX0208
  50          "\e$B!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2!3!4!5!6!7!8!9!:!;!<!=!>\e(B\
  51 \e$B!?!@!A!B!C!D!E!G!I!K!M!O!Q!S!U!W!Y![!k!l!m!n\e(B\
  52 \e$B$!$#$%$'$)$C$c$e$g$n%!%#%%%'%)%C%c%e%g%n%u%v\e(B"
  53          ;; Chinese GB2312
  54          "\e$A!"!##.#,!$!%!&!'!(!)!*!+!,!-!/!1#)!3!5!7!9!;!=\e(B\
  55 \e$A!?#;#:#?#!!@!A!B!C!c!d!e!f#/#\#"#_#~#|(e\e(B"
  56          ;; Chinese BIG5
  57          "\e$(0!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2\e(B\
  58 \e$(0!3!4!5!6!7!8!9!:!;!<!=!?!A!C!E!G!I!K\e(B\
  59 \e$(0!M!O!Q\e(B   \e$(0!S!U!W!Y![!]!_!a!c!e!g!i!k!q\e(B\
  60 \e$(0"#"$"%"&"'"(")"*"+","2"3"4"j"k"l"x%7\e(B"))
  61        (len (length kinsoku-bol))
  62        (idx 0)
  63        ch)
  64   (while (< idx len)
  65     (setq ch (sref kinsoku-bol idx)
  66           idx (+ idx (char-bytes ch)))
  67     (modify-category-entry ch ?>)))
  68
  69 ;; Setting character category `<' for characters which should not be
  70 ;; placed at end of line.
  71 (let* ((kinsoku-eol
  72         (concat
  73          ;; ASCII
  74          "({[`"
  75          ;; Japanese JISX0208
  76          "\e$B!F!H!J!L!N!P!R!T!V!X!Z!k!l!m!n!w!x\e(B\
  77 \e$A!.!0#"#(!2!4!6!8!:!<!>!c!d!e#@!f!l\e(B"
  78          ;; Chinese GB2312
  79          "\e$A(E(F(G(H(I(J(K(L(M(N(O(P(Q(R(S(T(U(V(W(X(Y(h\e(B\
  80 \e$(0!>!@!B!D!F!H!J!L!N!P!R!T!V!X!Z!\!^!`!b\e(B"
  81          ;; Chinese BIG5
  82          "\e$(0!d!f!h!j!k!q!p"i"j"k"n"x$u$v$w$x$y$z${\e(B\
  83 \e$(0$|$}$~%!%"%#%$%%%&%'%(%)%*%+%:\e(B"))
  84        (len (length kinsoku-eol))
  85        (idx 0)
  86        ch)
  87   (while (< idx len)
  88     (setq ch (sref kinsoku-eol idx)
  89           idx (+ idx (char-bytes ch)))
  90     (modify-category-entry ch ?<)))
  91
  92 ;; Try to resolve `kinsoku' restriction by making the current line longer.
  93 (defun kinsoku-longer ()
  94   (let ((pos-and-column (save-excursion
  95                           (forward-char 1)
  96                           (while (aref (char-category-set (following-char)) ?>)
  97                             (forward-char 1))
  98                           (cons (point) (current-column)))))
  99     (if (or (<= kinsoku-limit 0)
 100             (< (cdr pos-and-column) (+ (current-fill-column) kinsoku-limit)))
 101         (goto-char (car pos-and-column)))))
 102
 103 ;; Try to resolve `kinsoku' restriction by making the current line shorter.
 104 ;; The line can't be broken before the buffer position LINEBEG."
 105 (defun kinsoku-shorter (linebeg)
 106   (let ((pos (save-excursion
 107                (forward-char -1)
 108                (while (and (< linebeg (point))
 109                            (or (aref (char-category-set (preceding-char)) ?<)
 110                                (aref (char-category-set (following-char)) ?>)))
 111                  (forward-char -1))
 112                (point))))
 113     (if (< linebeg pos)
 114         (goto-char pos))))
 115
 116 ;;;###autoload
 117 (defun kinsoku (linebeg)
 118   "Go to a line breaking position near point by doing `kinsoku' processing.
 119 LINEBEG is a buffer position we can't break a line before.
 120
 121 `Kinsoku' processing is to prohibit specific characters to be placed
 122 at beginning of line or at end of line.  Characters not to be placed
 123 at beginning and end of line have character category `>' and `<'
 124 respectively.  This restriction is dissolved by making a line longer or
 125 shorter.
 126
 127 `Kinsoku' is a Japanese word which originally means ordering to stay
 128 in one place, and is used for the text processing described above in
 129 the context of text formatting."
 130   (if (or (and
 131            ;; The character after point can't be placed at beginning
 132            ;; of line.
 133            (aref (char-category-set (following-char)) ?>)
 134            ;; We at first try to dissolve this situation by making a
 135            ;; line longer.  If it fails, then try making a line
 136            ;; shorter.
 137            (not (kinsoku-longer)))
 138           ;; The character before point can't be placed at end of line.
 139           (aref (char-category-set (preceding-char)) ?<))
 140       (kinsoku-shorter linebeg)))
 141
 142 ;; kinsoku.el ends here