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 "character.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, up, 0, indices);
 142       map_char_table (shuffle, Qnil, 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, 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, eqv, 0, indices);
 157       map_char_table (shuffle, Qnil, canon, eqv, 0, indices);
 158       XCHAR_TABLE (table)->extras[2] = eqv;
 159     }
 160
 161   if (standard)
 162     Vascii_downcase_table = table;
 163   else
 164     {
 165       current_buffer->downcase_table = table;
 166       current_buffer->upcase_table = up;
 167       current_buffer->case_canon_table = canon;
 168       current_buffer->case_eqv_table = eqv;
 169     }
 170
 171   return table;
 172 }
 173 \f
 174 /* The following functions are called in map_char_table.  */
 175
 176 /*  Set CANON char-table element for C to a translated ELT by UP and
 177    DOWN char-tables.  This is done only when ELT is a character.  The
 178    char-tables CANON, UP, and DOWN are in CASE_TABLE.  */
 179
 180 static void
 181 set_canon (case_table, range, elt)
 182      Lisp_Object case_table, range, elt;
 183 {
 184   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 185   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 186   int from, to;
 187
 188   if (NATNUMP (elt))
 189     {
 190       if (CONSP (range))
 191         {
 192           from = XINT (XCAR (range));
 193           to = XINT (XCDR (range));
 194         }
 195       else
 196         from = to = XINT (range);
 197
 198       for (; from <= to; from++)
 199         {
 200           Lisp_Object val1, val2;
 201
 202           val1 = Faref (up, elt);
 203           if (EQ (val1, Qt))
 204             val1 = elt;
 205           else if (! NATNUMP (val1))
 206             continue;
 207           val2 = Faref (case_table, val1);
 208           if (EQ (val2, Qt))
 209             val2 = val1;
 210           else if (! NATNUMP (val2))
 211             continue;
 212           Faset (canon, make_number (from), val2);
 213         }
 214     }
 215 }
 216
 217 /* Set elements of char-table TABLE for characters in RANGE to
 218    themselves.  This is done only when ELT is a character.  This is
 219    called in map_char_table.  */
 220
 221 static void
 222 set_identity (table, range, elt)
 223      Lisp_Object table, range, elt;
 224 {
 225   if (EQ (elt, Qt) || NATNUMP (elt))
 226     Fset_char_table_range (table, range, Qt);
 227 }
 228
 229 /* Permute the elements of TABLE (which is initially an identity
 230    mapping) so that it has one cycle for each equivalence class
 231    induced by the translation table on which map_char_table is
 232    operated.  */
 233
 234 static void
 235 shuffle (table, range, elt)
 236      Lisp_Object table, range, elt;
 237 {
 238   int from, to;
 239
 240   if (NATNUMP (elt))
 241     {
 242       Lisp_Object tem;
 243
 244       if (CONSP (range))
 245         {
 246           from = XINT (XCAR (range));
 247           to = XINT (XCDR (range));
 248         }
 249       else
 250         from = to = XINT (range);
 251
 252       for (; from <= to; from++)
 253         if (from != XINT (elt))
 254           {
 255             tem = Faref (table, elt);
 256             if (EQ (tem, Qt))
 257               tem = elt;
 258             Faset (table, elt, make_number (from));
 259             Faset (table, make_number (from), tem);
 260           }
 261     }
 262 }
 263 \f
 264 void
 265 init_casetab_once ()
 266 {
 267   register int i;
 268   Lisp_Object down, up;
 269   Qcase_table = intern ("case-table");
 270   staticpro (&Qcase_table);
 271
 272   /* Intern this now in case it isn't already done.
 273      Setting this variable twice is harmless.
 274      But don't staticpro it here--that is done in alloc.c.  */
 275   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 276
 277   /* Now we are ready to set up this property, so we can
 278      create char tables.  */
 279   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 280
 281   down = Fmake_char_table (Qcase_table, Qnil);
 282   Vascii_downcase_table = down;
 283   XCHAR_TABLE (down)->purpose = Qcase_table;
 284
 285   for (i = 0; i < 128; i++)
 286     CHAR_TABLE_SET (down, i, (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 287
 288   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 289
 290   up = Fmake_char_table (Qcase_table, Qnil);
 291   XCHAR_TABLE (down)->extras[0] = up;
 292
 293   for (i = 0; i < 128; i++)
 294     CHAR_TABLE_SET (up, i, ((i >= 'A' && i <= 'Z')
 295                             ? i + ('a' - 'A')
 296                             : ((i >= 'a' && i <= 'z')
 297                                ? i + ('A' - 'a')
 298                                : i)));
 299
 300   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 301 }
 302
 303 void
 304 syms_of_casetab ()
 305 {
 306   Qcase_table_p = intern ("case-table-p");
 307   staticpro (&Qcase_table_p);
 308
 309   staticpro (&Vascii_canon_table);
 310   staticpro (&Vascii_downcase_table);
 311   staticpro (&Vascii_eqv_table);
 312   staticpro (&Vascii_upcase_table);
 313
 314   defsubr (&Scase_table_p);
 315   defsubr (&Scurrent_case_table);
 316   defsubr (&Sstandard_case_table);
 317   defsubr (&Sset_case_table);
 318   defsubr (&Sset_standard_case_table);
 319 }