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   "Return t iff OBJECT is a case table.\n\
  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   "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   "Return the standard case table.\n\
  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   "Select a new case table for the current buffer.\n\
  95 A case table is a char-table which maps characters\n\
  96 to their lower-case equivalents.  It also has three \"extra\" slots\n\
  97 which may be additional char-tables or nil.\n\
  98 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.\n\
  99 UPCASE maps each character to its upper-case equivalent;\n\
 100  if lower and upper case characters are in 1-1 correspondence,\n\
 101  you may use nil and the upcase table will be deduced from DOWNCASE.\n\
 102 CANONICALIZE maps each character to a canonical equivalent;\n\
 103  any two characters that are related by case-conversion have the same\n\
 104  canonical equivalent character; it may be nil, in which case it is\n\
 105  deduced from DOWNCASE and UPCASE.\n\
 106 EQUIVALENCES is a map that cyclicly permutes each equivalence class\n\
 107  (of characters with the same canonical equivalent); it may be nil,\n\
 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   "Select a new standard case table for new buffers.\n\
 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, c, elt)
 182      Lisp_Object case_table, c, elt;
 183 {
 184   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 185   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 186
 187   if (NATNUMP (elt))
 188     Faset (canon, c, Faref (case_table, Faref (up, elt)));
 189 }
 190
 191 /* Set elements of char-table TABLE for C to C itself.  This is done
 192    only when ELT is a character.  This is called in map_char_table.  */
 193
 194 static void
 195 set_identity (table, c, elt)
 196      Lisp_Object table, c, elt;
 197 {
 198   if (NATNUMP (elt))
 199     Faset (table, c, c);
 200 }
 201
 202 /* Permute the elements of TABLE (which is initially an identity
 203    mapping) so that it has one cycle for each equivalence class
 204    induced by the translation table on which map_char_table is
 205    operated.  */
 206
 207 static void
 208 shuffle (table, c, elt)
 209      Lisp_Object table, c, elt;
 210 {
 211   if (NATNUMP (elt) && !EQ (c, elt))
 212     {
 213       Lisp_Object tem = Faref (table, elt);
 214       Faset (table, elt, c);
 215       Faset (table, c, tem);
 216     }
 217 }
 218 \f
 219 void
 220 init_casetab_once ()
 221 {
 222   register int i;
 223   Lisp_Object down, up;
 224   Qcase_table = intern ("case-table");
 225   staticpro (&Qcase_table);
 226
 227   /* Intern this now in case it isn't already done.
 228      Setting this variable twice is harmless.
 229      But don't staticpro it here--that is done in alloc.c.  */
 230   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 231
 232   /* Now we are ready to set up this property, so we can
 233      create char tables.  */
 234   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 235
 236   down = Fmake_char_table (Qcase_table, Qnil);
 237   Vascii_downcase_table = down;
 238   XCHAR_TABLE (down)->purpose = Qcase_table;
 239
 240   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 241     XSETFASTINT (XCHAR_TABLE (down)->contents[i],
 242                  (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 243
 244   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 245
 246   up = Fmake_char_table (Qcase_table, Qnil);
 247   XCHAR_TABLE (down)->extras[0] = up;
 248
 249   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 250     XSETFASTINT (XCHAR_TABLE (up)->contents[i],
 251                  ((i >= 'A' && i <= 'Z')
 252                   ? i + ('a' - 'A')
 253                   : ((i >= 'a' && i <= 'z')
 254                      ? i + ('A' - 'a')
 255                      : i)));
 256
 257   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 258 }
 259
 260 void
 261 syms_of_casetab ()
 262 {
 263   Qcase_table_p = intern ("case-table-p");
 264   staticpro (&Qcase_table_p);
 265
 266   staticpro (&Vascii_canon_table);
 267   staticpro (&Vascii_downcase_table);
 268   staticpro (&Vascii_eqv_table);
 269   staticpro (&Vascii_upcase_table);
 270
 271   defsubr (&Scase_table_p);
 272   defsubr (&Scurrent_case_table);
 273   defsubr (&Sstandard_case_table);
 274   defsubr (&Sset_case_table);
 275   defsubr (&Sset_standard_case_table);
 276 }