lisp/international/kinsoku.el

   1 ;;; kinsoku.el --- `Kinsoku' processing funcs -*- coding: iso-2022-7bit; -*-
   2
   3 ;; Copyright (C) 1997, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   4 ;;   Free Software Foundation, Inc.
   5 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   6 ;;   2005, 2006, 2007, 2008
   7 ;;   National Institute of Advanced Industrial Science and Technology (AIST)
   8 ;;   Registration Number H14PRO021
   9
  10 ;; Keywords: mule, kinsoku
  11
  12 ;; This file is part of GNU Emacs.
  13
  14 ;; GNU Emacs is free software; you can redistribute it and/or modify
  15 ;; it under the terms of the GNU General Public License as published by
  16 ;; the Free Software Foundation; either version 3, or (at your option)
  17 ;; any later version.
  18
  19 ;; GNU Emacs is distributed in the hope that it will be useful,
  20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22 ;; GNU General Public License for more details.
  23
  24 ;; You should have received a copy of the GNU General Public License
  25 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  26 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  27 ;; Boston, MA 02110-1301, USA.
  28
  29 ;;; Commentary:
  30
  31 ;; `Kinsoku' processing is to prohibit specific characters to be
  32 ;; placed at beginning of line or at end of line.  Characters not to
  33 ;; be placed at beginning and end of line have character category `>'
  34 ;; and `<' respectively.   This restriction is dissolved by making a
  35 ;; line longer or shorter.
  36 ;;
  37 ;; `Kinsoku' is a Japanese word which originally means ordering to
  38 ;; stay in one place, and is used for the text processing described
  39 ;; above in the context of text formatting.
  40
  41 ;;; Code:
  42
  43 (defvar kinsoku-limit 4
  44   "How many more columns we can make lines longer by `kinsoku' processing.
  45 The value 0 means there's no limitation.")
  46
  47 ;; Setting character category `>' for characters which should not be
  48 ;; placed at beginning of line.
  49 (let* ((kinsoku-bol
  50         (concat
  51          ;; ASCII
  52          "!)-_~}]:;',.?"
  53          ;; Latin JISX0201
  54          ;; Instead of putting Latin JISX0201 string directly, we
  55          ;; generate the string as below to avoid character
  56          ;; unification problem.
  57          (let* ((str1 "!)-_~}]:;',.?")
  58                 (len (length str1))
  59                 (idx 0)
  60                 (str2 "")
  61                 ch)
  62            (while (< idx len)
  63              (setq ch (make-char 'latin-jisx0201 (aref str1 idx))
  64                    str2 (concat str2 (char-to-string ch))
  65                    idx (1+ idx)))
  66            str2)
  67          ;; Katakana JISX0201
  68          "\e(I!#'()*+,-./0^_\e(B"
  69          ;; Japanese JISX0208
  70          "\e$B!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2!3!4!5!6!7!8!9!:!;!<!=!>\e(B\
  71 \e$B!?!@!A!B!C!D!E!G!I!K!M!O!Q!S!U!W!Y![!k!l!m!n\e(B\
  72 \e$B$!$#$%$'$)$C$c$e$g$n%!%#%%%'%)%C%c%e%g%n%u%v\e(B"
  73          ;; Chinese GB2312
  74          "\e$A!"!##.#,!$!%!&!'!(!)!*!+!,!-!/!1#)!3!5!7!9!;!=\e(B\
  75 \e$A!?#;#:#?#!!@!A!B!C!c!d!e!f#/#\#"#_#~#|(e\e(B"
  76          ;; Chinese BIG5
  77          "\e$(0!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2\e(B\
  78 \e$(0!3!4!5!6!7!8!9!:!;!<!=!?!A!C!E!G!I!K\e(B\
  79 \e$(0!M!O!Q!S!U!W!Y![!]!_!a!c!e!g!i!k!q\e(B\
  80 \e$(0"#"$"%"&"'"(")"*"+","2"3"4"j"k"l"x%7\e(B"))
  81        (len (length kinsoku-bol))
  82        (idx 0)
  83        ch)
  84   (while (< idx len)
  85     (setq ch (aref kinsoku-bol idx)
  86           idx (1+ idx))
  87     (modify-category-entry ch ?>)))
  88
  89 ;; Setting character category `<' for characters which should not be
  90 ;; placed at end of line.
  91 (let* ((kinsoku-eol
  92         (concat
  93          ;; ASCII
  94          "({[`"
  95          ;; Latin JISX0201
  96          ;; See the comment above.
  97          (let* ((str1 "({[`")
  98                 (len (length str1))
  99                 (idx 0)
 100                 (str2 "")
 101                 ch)
 102            (while (< idx len)
 103              (setq ch (make-char 'latin-jisx0201 (aref str1 idx))
 104                    str2 (concat str2 (char-to-string ch))
 105                    idx (1+ idx)))
 106            str2)
 107          ;; JISX0201 Katakana
 108          "\e(I"\e(B"
 109          ;; Japanese JISX0208
 110          "\e$B!F!H!J!L!N!P!R!T!V!X!Z!k!l!m!n!w!x\e(B\
 111 \e$A!.!0#"#(!2!4!6!8!:!<!>!c!d!e#@!f!l\e(B"
 112          ;; Chinese GB2312
 113          "\e$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\
 114 \\e$(0!>!@!B!D!F!H!J!L!N!P!R!T!V!X!Z!\!^!`!b\e(B"
 115          ;; Chinese BIG5
 116          "\e$(0!d!f!h!j!k!q!p"i"j"k"n"x$u$v$w$x$y$z${\e(B\
 117 \e$(0$|$}$~%!%"%#%$%%%&%'%(%)%*%+%:\e(B"))
 118        (len (length kinsoku-eol))
 119        (idx 0)
 120        ch)
 121   (while (< idx len)
 122     (setq ch (aref kinsoku-eol idx)
 123           idx (1+ idx))
 124     (modify-category-entry ch ?<)))
 125
 126 ;; Try to resolve `kinsoku' restriction by making the current line longer.
 127 (defun kinsoku-longer ()
 128   (let ((pos-and-column
 129          (save-excursion
 130            (forward-char 1)
 131            (while (and (not (eolp))
 132                        (or (aref (char-category-set (following-char)) ?>)
 133                            ;; protect non-kinsoku words
 134                            (not (or (eq (preceding-char) ? )
 135                                     (aref (char-category-set (preceding-char))
 136                                           ?|)))))
 137              (forward-char 1))
 138            (cons (point) (current-column)))))
 139     (if (or (<= kinsoku-limit 0)
 140             (< (cdr pos-and-column) (+ (current-fill-column) kinsoku-limit)))
 141         (goto-char (car pos-and-column)))))
 142
 143 ;; Try to resolve `kinsoku' restriction by making the current line shorter.
 144 ;; The line can't be broken before the buffer position LINEBEG.
 145 (defun kinsoku-shorter (linebeg)
 146   (let ((pos (save-excursion
 147                (forward-char -1)
 148                (while (and
 149                        (< linebeg (point))
 150                        (or (aref (char-category-set (preceding-char)) ?<)
 151                            (aref (char-category-set (following-char)) ?>)
 152                            ;; protect non-kinsoku words
 153                            (not (or (eq (preceding-char) ? )
 154                                     (aref (char-category-set (preceding-char))
 155                                           ?|)))))
 156                  (forward-char -1))
 157                (point))))
 158     (if (< linebeg pos)
 159         (goto-char pos))))
 160
 161 ;;;###autoload
 162 (defun kinsoku (linebeg)
 163   "Go to a line breaking position near point by doing `kinsoku' processing.
 164 LINEBEG is a buffer position we can't break a line before.
 165
 166 `Kinsoku' processing is to prohibit specific characters to be placed
 167 at beginning of line or at end of line.  Characters not to be placed
 168 at beginning and end of line have character category `>' and `<'
 169 respectively.  This restriction is dissolved by making a line longer or
 170 shorter.
 171
 172 `Kinsoku' is a Japanese word which originally means ordering to stay
 173 in one place, and is used for the text processing described above in
 174 the context of text formatting."
 175   (if enable-kinsoku
 176       (if (or (and
 177                ;; The character after point can't be placed at beginning
 178                ;; of line.
 179                (aref (char-category-set (following-char)) ?>)
 180                ;; We at first try to dissolve this situation by making a
 181                ;; line longer.  If it fails, then try making a line
 182                ;; shorter.
 183                (not (kinsoku-longer)))
 184               ;; The character before point can't be placed at end of line.
 185               (aref (char-category-set (preceding-char)) ?<))
 186           (kinsoku-shorter linebeg))))
 187
 188 ;; arch-tag: e6b036bc-9e5b-4e9f-a22c-4ed04e37777e
 189 ;;; kinsoku.el ends here