src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993, 1994, 2002, 2003, 2004,
   3                  2005 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, USA.  */
  21
  22 /* Written by Howard Gayle.  */
  23
  24 #include <config.h>
  25 #include "lisp.h"
  26 #include "buffer.h"
  27 #include "charset.h"
  28
  29 Lisp_Object Qcase_table_p, Qcase_table;
  30 Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
  31 Lisp_Object Vascii_canon_table, Vascii_eqv_table;
  32
  33 /* Used as a temporary in DOWNCASE and other macros in lisp.h.  No
  34    need to mark it, since it is used only very temporarily.  */
  35 int case_temp1;
  36 Lisp_Object case_temp2;
  37
  38 static void set_canon ();
  39 static void set_identity ();
  40 static void shuffle ();
  41
  42 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  43        doc: /* Return t iff OBJECT is a case table.
  44 See `set-case-table' for more information on these data structures.  */)
  45      (object)
  46      Lisp_Object object;
  47 {
  48   Lisp_Object up, canon, eqv;
  49
  50   if (! CHAR_TABLE_P (object))
  51     return Qnil;
  52   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
  53     return Qnil;
  54
  55   up = XCHAR_TABLE (object)->extras[0];
  56   canon = XCHAR_TABLE (object)->extras[1];
  57   eqv = XCHAR_TABLE (object)->extras[2];
  58
  59   return ((NILP (up) || CHAR_TABLE_P (up))
  60           && ((NILP (canon) && NILP (eqv))
  61               || (CHAR_TABLE_P (canon)
  62                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
  63           ? Qt : Qnil);
  64 }
  65
  66 static Lisp_Object
  67 check_case_table (obj)
  68      Lisp_Object obj;
  69 {
  70   register Lisp_Object tem;
  71
  72   while (tem = Fcase_table_p (obj), NILP (tem))
  73     obj = wrong_type_argument (Qcase_table_p, obj);
  74   return (obj);
  75 }
  76
  77 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  78        doc: /* Return the case table of the current buffer.  */)
  79      ()
  80 {
  81   return current_buffer->downcase_table;
  82 }
  83
  84 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  85        doc: /* Return the standard case table.
  86 This is the one used for new buffers.  */)
  87      ()
  88 {
  89   return Vascii_downcase_table;
  90 }
  91
  92 static Lisp_Object set_case_table ();
  93
  94 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  95        doc: /* Select a new case table for the current buffer.
  96 A case table is a char-table which maps characters
  97 to their lower-case equivalents.  It also has three \"extra\" slots
  98 which may be additional char-tables or nil.
  99 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
 100 UPCASE maps each character to its upper-case equivalent;
 101  if lower and upper case characters are in 1-1 correspondence,
 102  you may use nil and the upcase table will be deduced from DOWNCASE.
 103 CANONICALIZE maps each character to a canonical equivalent;
 104  any two characters that are related by case-conversion have the same
 105  canonical equivalent character; it may be nil, in which case it is
 106  deduced from DOWNCASE and UPCASE.
 107 EQUIVALENCES is a map that cyclicly permutes each equivalence class
 108  (of characters with the same canonical equivalent); it may be nil,
 109  in which case it is deduced from CANONICALIZE.  */)
 110      (table)
 111      Lisp_Object table;
 112 {
 113   return set_case_table (table, 0);
 114 }
 115
 116 DEFUN ("set-standard-case-table", Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
 117        doc: /* Select a new standard case table for new buffers.
 118 See `set-case-table' for more info on case tables.  */)
 119      (table)
 120      Lisp_Object table;
 121 {
 122   return set_case_table (table, 1);
 123 }
 124
 125 static Lisp_Object
 126 set_case_table (table, standard)
 127      Lisp_Object table;
 128      int standard;
 129 {
 130   Lisp_Object up, canon, eqv;
 131   Lisp_Object indices[3];
 132
 133   check_case_table (table);
 134
 135   up = XCHAR_TABLE (table)->extras[0];
 136   canon = XCHAR_TABLE (table)->extras[1];
 137   eqv = XCHAR_TABLE (table)->extras[2];
 138
 139   if (NILP (up))
 140     {
 141       up = Fmake_char_table (Qcase_table, Qnil);
 142       map_char_table (set_identity, Qnil, table, table, up, 0, indices);
 143       map_char_table (shuffle, Qnil, table, table, up, 0, indices);
 144       XCHAR_TABLE (table)->extras[0] = up;
 145     }
 146
 147   if (NILP (canon))
 148     {
 149       canon = Fmake_char_table (Qcase_table, Qnil);
 150       XCHAR_TABLE (table)->extras[1] = canon;
 151       map_char_table (set_canon, Qnil, table, table, table, 0, indices);
 152     }
 153
 154   if (NILP (eqv))
 155     {
 156       eqv = Fmake_char_table (Qcase_table, Qnil);
 157       map_char_table (set_identity, Qnil, canon, canon, eqv, 0, indices);
 158       map_char_table (shuffle, Qnil, canon, canon, eqv, 0, indices);
 159       XCHAR_TABLE (table)->extras[2] = eqv;
 160     }
 161
 162   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 163   XCHAR_TABLE (canon)->extras[2] = eqv;
 164
 165   if (standard)
 166     {
 167       Vascii_downcase_table = table;
 168       Vascii_upcase_table = up;
 169       Vascii_canon_table = canon;
 170       Vascii_eqv_table = eqv;
 171     }
 172   else
 173     {
 174       current_buffer->downcase_table = table;
 175       current_buffer->upcase_table = up;
 176       current_buffer->case_canon_table = canon;
 177       current_buffer->case_eqv_table = eqv;
 178     }
 179
 180   return table;
 181 }
 182 \f
 183 /* The following functions are called in map_char_table.  */
 184
 185 /*  Set CANON char-table element for C to a translated ELT by UP and
 186    DOWN char-tables.  This is done only when ELT is a character.  The
 187    char-tables CANON, UP, and DOWN are in CASE_TABLE.  */
 188
 189 static void
 190 set_canon (case_table, c, elt)
 191      Lisp_Object case_table, c, elt;
 192 {
 193   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 194   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 195
 196   if (NATNUMP (elt))
 197     Faset (canon, c, Faref (case_table, Faref (up, elt)));
 198 }
 199
 200 /* Set elements of char-table TABLE for C to C itself.  This is done
 201    only when ELT is a character.  This is called in map_char_table.  */
 202
 203 static void
 204 set_identity (table, c, elt)
 205      Lisp_Object table, c, elt;
 206 {
 207   if (NATNUMP (elt))
 208     Faset (table, c, c);
 209 }
 210
 211 /* Permute the elements of TABLE (which is initially an identity
 212    mapping) so that it has one cycle for each equivalence class
 213    induced by the translation table on which map_char_table is
 214    operated.  */
 215
 216 static void
 217 shuffle (table, c, elt)
 218      Lisp_Object table, c, elt;
 219 {
 220   if (NATNUMP (elt) && !EQ (c, elt))
 221     {
 222       Lisp_Object tem = Faref (table, elt);
 223       Faset (table, elt, c);
 224       Faset (table, c, tem);
 225     }
 226 }
 227 \f
 228 void
 229 init_casetab_once ()
 230 {
 231   register int i;
 232   Lisp_Object down, up;
 233   Qcase_table = intern ("case-table");
 234   staticpro (&Qcase_table);
 235
 236   /* Intern this now in case it isn't already done.
 237      Setting this variable twice is harmless.
 238      But don't staticpro it here--that is done in alloc.c.  */
 239   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 240
 241   /* Now we are ready to set up this property, so we can
 242      create char tables.  */
 243   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 244
 245   down = Fmake_char_table (Qcase_table, Qnil);
 246   Vascii_downcase_table = down;
 247   XCHAR_TABLE (down)->purpose = Qcase_table;
 248
 249   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 250     XSETFASTINT (XCHAR_TABLE (down)->contents[i],
 251                  (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 252
 253   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 254
 255   up = Fmake_char_table (Qcase_table, Qnil);
 256   XCHAR_TABLE (down)->extras[0] = up;
 257
 258   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 259     XSETFASTINT (XCHAR_TABLE (up)->contents[i],
 260                  ((i >= 'A' && i <= 'Z')
 261                   ? i + ('a' - 'A')
 262                   : ((i >= 'a' && i <= 'z')
 263                      ? i + ('A' - 'a')
 264                      : i)));
 265
 266   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 267 }
 268
 269 void
 270 syms_of_casetab ()
 271 {
 272   Qcase_table_p = intern ("case-table-p");
 273   staticpro (&Qcase_table_p);
 274
 275   staticpro (&Vascii_canon_table);
 276   staticpro (&Vascii_downcase_table);
 277   staticpro (&Vascii_eqv_table);
 278   staticpro (&Vascii_upcase_table);
 279
 280   defsubr (&Scase_table_p);
 281   defsubr (&Scurrent_case_table);
 282   defsubr (&Sstandard_case_table);
 283   defsubr (&Sset_case_table);
 284   defsubr (&Sset_standard_case_table);
 285 }
 286
 287 /* arch-tag: e06388ad-99fe-40ec-ba67-9d010fcc4916
 288    (do not change this comment) */