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 of the License, or
  17 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  26
  27 ;;; Commentary:
  28
  29 ;; `Kinsoku' processing is to prohibit specific characters to be
  30 ;; placed at beginning of line or at end of line.  Characters not to
  31 ;; be placed at beginning and end of line have character category `>'
  32 ;; and `<' respectively.   This restriction is dissolved by making a
  33 ;; line longer or shorter.
  34 ;;
  35 ;; `Kinsoku' is a Japanese word which originally means ordering to
  36 ;; stay in one place, and is used for the text processing described
  37 ;; above in the context of text formatting.
  38
  39 ;;; Code:
  40
  41 (defvar kinsoku-limit 4
  42   "How many more columns we can make lines longer by `kinsoku' processing.
  43 The value 0 means there's no limitation.")
  44
  45 ;; Setting character category `>' for characters which should not be
  46 ;; placed at beginning of line.
  47 (let* ((kinsoku-bol
  48         (concat
  49          ;; ASCII
  50          "!)-_~}]:;',.?"
  51          ;; Latin JISX0201
  52          ;; Instead of putting Latin JISX0201 string directly, we
  53          ;; generate the string as below to avoid character
  54          ;; unification problem.
  55          (let* ((str1 "!)-_~}]:;',.?")
  56                 (len (length str1))
  57                 (idx 0)
  58                 (str2 "")
  59                 ch)
  60            (while (< idx len)
  61              (setq ch (make-char 'latin-jisx0201 (aref str1 idx))
  62                    str2 (concat str2 (char-to-string ch))
  63                    idx (1+ idx)))
  64            str2)
  65          ;; Katakana JISX0201
  66          "\e(I!#'()*+,-./0^_\e(B"
  67          ;; Japanese JISX0208
  68          "\e$B!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2!3!4!5!6!7!8!9!:!;!<!=!>\e(B\
  69 \e$B!?!@!A!B!C!D!E!G!I!K!M!O!Q!S!U!W!Y![!k!l!m!n\e(B\
  70 \e$B$!$#$%$'$)$C$c$e$g$n%!%#%%%'%)%C%c%e%g%n%u%v\e(B"
  71          ;; Chinese GB2312
  72          "\e$A!"!##.#,!$!%!&!'!(!)!*!+!,!-!/!1#)!3!5!7!9!;!=\e(B\
  73 \e$A!?#;#:#?#!!@!A!B!C!c!d!e!f#/#\#"#_#~#|(e\e(B"
  74          ;; Chinese BIG5
  75          "\e$(0!"!#!$!%!&!'!(!)!*!+!,!-!.!/!0!1!2\e(B\
  76 \e$(0!3!4!5!6!7!8!9!:!;!<!=!?!A!C!E!G!I!K\e(B\
  77 \e$(0!M!O!Q!S!U!W!Y![!]!_!a!c!e!g!i!k!q\e(B\
  78 \e$(0"#"$"%"&"'"(")"*"+","2"3"4"j"k"l"x%7\e(B"))
  79        (len (length kinsoku-bol))
  80        (idx 0)
  81        ch)
  82   (while (< idx len)
  83     (setq ch (aref kinsoku-bol idx)
  84           idx (1+ idx))
  85     (modify-category-entry ch ?>)))
  86
  87 ;; Setting character category `<' for characters which should not be
  88 ;; placed at end of line.
  89 (let* ((kinsoku-eol
  90         (concat
  91          ;; ASCII
  92          "({[`"
  93          ;; Latin JISX0201
  94          ;; See the comment above.
  95          (let* ((str1 "({[`")
  96                 (len (length str1))
  97                 (idx 0)
  98                 (str2 "")
  99                 ch)
 100            (while (< idx len)
 101              (setq ch (make-char 'latin-jisx0201 (aref str1 idx))
 102                    str2 (concat str2 (char-to-string ch))
 103                    idx (1+ idx)))
 104            str2)
 105          ;; JISX0201 Katakana
 106          "\e(I"\e(B"
 107          ;; Japanese JISX0208
 108          "\e$B!F!H!J!L!N!P!R!T!V!X!Z!k!l!m!n!w!x\e(B\
 109 \e$A!.!0#"#(!2!4!6!8!:!<!>!c!d!e#@!f!l\e(B"
 110          ;; Chinese GB2312
 111          "\e$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\
 112 \\e$(0!>!@!B!D!F!H!J!L!N!P!R!T!V!X!Z!\!^!`!b\e(B"
 113          ;; Chinese BIG5
 114          "\e$(0!d!f!h!j!k!q!p"i"j"k"n"x$u$v$w$x$y$z${\e(B\
 115 \e$(0$|$}$~%!%"%#%$%%%&%'%(%)%*%+%:\e(B"))
 116        (len (length kinsoku-eol))
 117        (idx 0)
 118        ch)
 119   (while (< idx len)
 120     (setq ch (aref kinsoku-eol idx)
 121           idx (1+ idx))
 122     (modify-category-entry ch ?<)))
 123
 124 ;; Try to resolve `kinsoku' restriction by making the current line longer.
 125 (defun kinsoku-longer ()
 126   (let ((pos-and-column
 127          (save-excursion
 128            (forward-char 1)
 129            (while (and (not (eolp))
 130                        (or (aref (char-category-set (following-char)) ?>)
 131                            ;; protect non-kinsoku words
 132                            (not (or (eq (preceding-char) ? )
 133                                     (aref (char-category-set (preceding-char))
 134                                           ?|)))))
 135              (forward-char 1))
 136            (cons (point) (current-column)))))
 137     (if (or (<= kinsoku-limit 0)
 138             (< (cdr pos-and-column) (+ (current-fill-column) kinsoku-limit)))
 139         (goto-char (car pos-and-column)))))
 140
 141 ;; Try to resolve `kinsoku' restriction by making the current line shorter.
 142 ;; The line can't be broken before the buffer position LINEBEG.
 143 (defun kinsoku-shorter (linebeg)
 144   (let ((pos (save-excursion
 145                (forward-char -1)
 146                (while (and
 147                        (< linebeg (point))
 148                        (or (aref (char-category-set (preceding-char)) ?<)
 149                            (aref (char-category-set (following-char)) ?>)
 150                            ;; protect non-kinsoku words
 151                            (not (or (eq (preceding-char) ? )
 152                                     (aref (char-category-set (preceding-char))
 153                                           ?|)))))
 154                  (forward-char -1))
 155                (point))))
 156     (if (< linebeg pos)
 157         (goto-char pos))))
 158
 159 ;;;###autoload
 160 (defun kinsoku (linebeg)
 161   "Go to a line breaking position near point by doing `kinsoku' processing.
 162 LINEBEG is a buffer position we can't break a line before.
 163
 164 `Kinsoku' processing is to prohibit specific characters to be placed
 165 at beginning of line or at end of line.  Characters not to be placed
 166 at beginning and end of line have character category `>' and `<'
 167 respectively.  This restriction is dissolved by making a line longer or
 168 shorter.
 169
 170 `Kinsoku' is a Japanese word which originally means ordering to stay
 171 in one place, and is used for the text processing described above in
 172 the context of text formatting."
 173   (if enable-kinsoku
 174       (if (or (and
 175                ;; The character after point can't be placed at beginning
 176                ;; of line.
 177                (aref (char-category-set (following-char)) ?>)
 178                ;; We at first try to dissolve this situation by making a
 179                ;; line longer.  If it fails, then try making a line
 180                ;; shorter.
 181                (not (kinsoku-longer)))
 182               ;; The character before point can't be placed at end of line.
 183               (aref (char-category-set (preceding-char)) ?<))
 184           (kinsoku-shorter linebeg))))
 185
 186 ;; arch-tag: e6b036bc-9e5b-4e9f-a22c-4ed04e37777e
 187 ;;; kinsoku.el ends here