src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 /* Written by Howard Gayle.  See chartab.c for details. */
  22
  23 #include <config.h>
  24 #include "lisp.h"
  25 #include "buffer.h"
  26 #include "charset.h"
  27
  28 Lisp_Object Qcase_table_p, Qcase_table;
  29 Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
  30 Lisp_Object Vascii_canon_table, Vascii_eqv_table;
  31
  32 /* Used as a temporary in DOWNCASE and other macros in lisp.h.  No
  33    need to mark it, since it is used only very temporarily.  */
  34 int case_temp1;
  35 Lisp_Object case_temp2;
  36
  37 static void set_canon ();
  38 static void set_identity ();
  39 static void shuffle ();
  40
  41 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  42        doc: /* Return t iff OBJECT is a case table.
  43 See `set-case-table' for more information on these data structures.  */)
  44      (object)
  45      Lisp_Object object;
  46 {
  47   Lisp_Object up, canon, eqv;
  48
  49   if (! CHAR_TABLE_P (object))
  50     return Qnil;
  51   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
  52     return Qnil;
  53
  54   up = XCHAR_TABLE (object)->extras[0];
  55   canon = XCHAR_TABLE (object)->extras[1];
  56   eqv = XCHAR_TABLE (object)->extras[2];
  57
  58   return ((NILP (up) || CHAR_TABLE_P (up))
  59           && ((NILP (canon) && NILP (eqv))
  60               || (CHAR_TABLE_P (canon)
  61                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
  62           ? Qt : Qnil);
  63 }
  64
  65 static Lisp_Object
  66 check_case_table (obj)
  67      Lisp_Object obj;
  68 {
  69   register Lisp_Object tem;
  70
  71   while (tem = Fcase_table_p (obj), NILP (tem))
  72     obj = wrong_type_argument (Qcase_table_p, obj);
  73   return (obj);
  74 }
  75
  76 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  77        doc: /* Return the case table of the current buffer.  */)
  78      ()
  79 {
  80   return current_buffer->downcase_table;
  81 }
  82
  83 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  84        doc: /* Return the standard case table.
  85 This is the one used for new buffers.  */)
  86      ()
  87 {
  88   return Vascii_downcase_table;
  89 }
  90
  91 static Lisp_Object set_case_table ();
  92
  93 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  94        doc: /* Select a new case table for the current buffer.
  95 A case table is a char-table which maps characters
  96 to their lower-case equivalents.  It also has three \"extra\" slots
  97 which may be additional char-tables or nil.
  98 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
  99 UPCASE maps each character to its upper-case equivalent;
 100  if lower and upper case characters are in 1-1 correspondence,
 101  you may use nil and the upcase table will be deduced from DOWNCASE.
 102 CANONICALIZE maps each character to a canonical equivalent;
 103  any two characters that are related by case-conversion have the same
 104  canonical equivalent character; it may be nil, in which case it is
 105  deduced from DOWNCASE and UPCASE.
 106 EQUIVALENCES is a map that cyclicly permutes each equivalence class
 107  (of characters with the same canonical equivalent); it may be nil,
 108  in which case it is deduced from CANONICALIZE.  */)
 109      (table)
 110      Lisp_Object table;
 111 {
 112   return set_case_table (table, 0);
 113 }
 114
 115 DEFUN ("set-standard-case-table", Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
 116        doc: /* Select a new standard case table for new buffers.
 117 See `set-case-table' for more info on case tables.  */)
 118      (table)
 119      Lisp_Object table;
 120 {
 121   return set_case_table (table, 1);
 122 }
 123
 124 static Lisp_Object
 125 set_case_table (table, standard)
 126      Lisp_Object table;
 127      int standard;
 128 {
 129   Lisp_Object up, canon, eqv;
 130   Lisp_Object indices[3];
 131
 132   check_case_table (table);
 133
 134   up = XCHAR_TABLE (table)->extras[0];
 135   canon = XCHAR_TABLE (table)->extras[1];
 136   eqv = XCHAR_TABLE (table)->extras[2];
 137
 138   if (NILP (up))
 139     {
 140       up = Fmake_char_table (Qcase_table, Qnil);
 141       map_char_table (set_identity, Qnil, table, table, up, 0, indices);
 142       map_char_table (shuffle, Qnil, table, table, up, 0, indices);
 143       XCHAR_TABLE (table)->extras[0] = up;
 144     }
 145
 146   if (NILP (canon))
 147     {
 148       canon = Fmake_char_table (Qcase_table, Qnil);
 149       XCHAR_TABLE (table)->extras[1] = canon;
 150       map_char_table (set_canon, Qnil, table, table, table, 0, indices);
 151     }
 152
 153   if (NILP (eqv))
 154     {
 155       eqv = Fmake_char_table (Qcase_table, Qnil);
 156       map_char_table (set_identity, Qnil, canon, canon, eqv, 0, indices);
 157       map_char_table (shuffle, Qnil, canon, canon, eqv, 0, indices);
 158       XCHAR_TABLE (table)->extras[2] = eqv;
 159     }
 160
 161   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 162   XCHAR_TABLE (canon)->extras[2] = eqv;
 163
 164   if (standard)
 165     Vascii_downcase_table = table;
 166   else
 167     {
 168       current_buffer->downcase_table = table;
 169       current_buffer->upcase_table = up;
 170       current_buffer->case_canon_table = canon;
 171       current_buffer->case_eqv_table = eqv;
 172     }
 173
 174   return table;
 175 }
 176 \f
 177 /* The following functions are called in map_char_table.  */
 178
 179 /*  Set CANON char-table element for C to a translated ELT by UP and
 180    DOWN char-tables.  This is done only when ELT is a character.  The
 181    char-tables CANON, UP, and DOWN are in CASE_TABLE.  */
 182
 183 static void
 184 set_canon (case_table, c, elt)
 185      Lisp_Object case_table, c, elt;
 186 {
 187   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 188   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 189
 190   if (NATNUMP (elt))
 191     Faset (canon, c, Faref (case_table, Faref (up, elt)));
 192 }
 193
 194 /* Set elements of char-table TABLE for C to C itself.  This is done
 195    only when ELT is a character.  This is called in map_char_table.  */
 196
 197 static void
 198 set_identity (table, c, elt)
 199      Lisp_Object table, c, elt;
 200 {
 201   if (NATNUMP (elt))
 202     Faset (table, c, c);
 203 }
 204
 205 /* Permute the elements of TABLE (which is initially an identity
 206    mapping) so that it has one cycle for each equivalence class
 207    induced by the translation table on which map_char_table is
 208    operated.  */
 209
 210 static void
 211 shuffle (table, c, elt)
 212      Lisp_Object table, c, elt;
 213 {
 214   if (NATNUMP (elt) && !EQ (c, elt))
 215     {
 216       Lisp_Object tem = Faref (table, elt);
 217       Faset (table, elt, c);
 218       Faset (table, c, tem);
 219     }
 220 }
 221 \f
 222 void
 223 init_casetab_once ()
 224 {
 225   register int i;
 226   Lisp_Object down, up;
 227   Qcase_table = intern ("case-table");
 228   staticpro (&Qcase_table);
 229
 230   /* Intern this now in case it isn't already done.
 231      Setting this variable twice is harmless.
 232      But don't staticpro it here--that is done in alloc.c.  */
 233   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 234
 235   /* Now we are ready to set up this property, so we can
 236      create char tables.  */
 237   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 238
 239   down = Fmake_char_table (Qcase_table, Qnil);
 240   Vascii_downcase_table = down;
 241   XCHAR_TABLE (down)->purpose = Qcase_table;
 242
 243   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 244     XSETFASTINT (XCHAR_TABLE (down)->contents[i],
 245                  (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 246
 247   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 248
 249   up = Fmake_char_table (Qcase_table, Qnil);
 250   XCHAR_TABLE (down)->extras[0] = up;
 251
 252   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 253     XSETFASTINT (XCHAR_TABLE (up)->contents[i],
 254                  ((i >= 'A' && i <= 'Z')
 255                   ? i + ('a' - 'A')
 256                   : ((i >= 'a' && i <= 'z')
 257                      ? i + ('A' - 'a')
 258                      : i)));
 259
 260   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 261 }
 262
 263 void
 264 syms_of_casetab ()
 265 {
 266   Qcase_table_p = intern ("case-table-p");
 267   staticpro (&Qcase_table_p);
 268
 269   staticpro (&Vascii_canon_table);
 270   staticpro (&Vascii_downcase_table);
 271   staticpro (&Vascii_eqv_table);
 272   staticpro (&Vascii_upcase_table);
 273
 274   defsubr (&Scase_table_p);
 275   defsubr (&Scurrent_case_table);
 276   defsubr (&Sstandard_case_table);
 277   defsubr (&Sset_case_table);
 278   defsubr (&Sset_standard_case_table);
 279 }