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
 131   check_case_table (table);
 132
 133   up = XCHAR_TABLE (table)->extras[0];
 134   canon = XCHAR_TABLE (table)->extras[1];
 135   eqv = XCHAR_TABLE (table)->extras[2];
 136
 137   if (NILP (up))
 138     {
 139       up = Fmake_char_table (Qcase_table, Qnil);
 140       map_char_table (set_identity, Qnil, table, up);
 141       map_char_table (shuffle, Qnil, table, up);
 142       XCHAR_TABLE (table)->extras[0] = up;
 143     }
 144
 145   if (NILP (canon))
 146     {
 147       canon = Fmake_char_table (Qcase_table, Qnil);
 148       XCHAR_TABLE (table)->extras[1] = canon;
 149       map_char_table (set_canon, Qnil, table, table);
 150     }
 151
 152   if (NILP (eqv))
 153     {
 154       eqv = Fmake_char_table (Qcase_table, Qnil);
 155       map_char_table (set_identity, Qnil, canon, eqv);
 156       map_char_table (shuffle, Qnil, canon, eqv);
 157       XCHAR_TABLE (table)->extras[2] = eqv;
 158     }
 159
 160   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 161   XCHAR_TABLE (canon)->extras[2] = eqv;
 162
 163   if (standard)
 164     Vascii_downcase_table = table;
 165   else
 166     {
 167       current_buffer->downcase_table = table;
 168       current_buffer->upcase_table = up;
 169       current_buffer->case_canon_table = canon;
 170       current_buffer->case_eqv_table = eqv;
 171     }
 172
 173   return table;
 174 }
 175 \f
 176 /* The following functions are called in map_char_table.  */
 177
 178 /* Set CANON char-table element for characters in RANGE to a
 179    translated ELT by UP and DOWN char-tables.  This is done only when
 180    ELT is a character.  The char-tables CANON, UP, and DOWN are in
 181    CASE_TABLE.  */
 182
 183 static void
 184 set_canon (case_table, range, elt)
 185      Lisp_Object case_table, range, 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     Fset_char_table_range (canon, range, Faref (case_table, Faref (up, elt)));
 192 }
 193
 194 /* Set elements of char-table TABLE for C to C itself.  C may be a
 195    cons specifying a character range.  In that case, set characters in
 196    that range to themselves.  This is done only when ELT is a
 197    character.  This is called in map_char_table.  */
 198
 199 static void
 200 set_identity (table, c, elt)
 201      Lisp_Object table, c, elt;
 202 {
 203   if (NATNUMP (elt))
 204     {
 205       int from, to;
 206
 207       if (CONSP (c))
 208         {
 209           from = XINT (XCAR (c));
 210           to = XINT (XCDR (c));
 211         }
 212       else
 213         from = to = XINT (c);
 214       for (; from <= to; from++)
 215         CHAR_TABLE_SET (table, from, make_number (from));
 216     }
 217 }
 218
 219 /* Permute the elements of TABLE (which is initially an identity
 220    mapping) so that it has one cycle for each equivalence class
 221    induced by the translation table on which map_char_table is
 222    operated.  */
 223
 224 static void
 225 shuffle (table, c, elt)
 226      Lisp_Object table, c, elt;
 227 {
 228   if (NATNUMP (elt))
 229     {
 230       Lisp_Object tem = Faref (table, elt);
 231       int from, to;
 232
 233       if (CONSP (c))
 234         {
 235           from = XINT (XCAR (c));
 236           to = XINT (XCDR (c));
 237         }
 238       else
 239         from = to = XINT (c);
 240
 241       for (; from <= to; from++)
 242         if (from != XINT (elt))
 243           {
 244             Faset (table, elt, make_number (from));
 245             Faset (table, make_number (from), tem);
 246           }
 247     }
 248 }
 249 \f
 250 void
 251 init_casetab_once ()
 252 {
 253   register int i;
 254   Lisp_Object down, up;
 255   Qcase_table = intern ("case-table");
 256   staticpro (&Qcase_table);
 257
 258   /* Intern this now in case it isn't already done.
 259      Setting this variable twice is harmless.
 260      But don't staticpro it here--that is done in alloc.c.  */
 261   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 262
 263   /* Now we are ready to set up this property, so we can
 264      create char tables.  */
 265   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 266
 267   down = Fmake_char_table (Qcase_table, Qnil);
 268   Vascii_downcase_table = down;
 269   XCHAR_TABLE (down)->purpose = Qcase_table;
 270
 271   for (i = 0; i < 128; i++)
 272     {
 273       int c = (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i;
 274       CHAR_TABLE_SET (down, i, make_number (c));
 275     }
 276
 277   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 278
 279   up = Fmake_char_table (Qcase_table, Qnil);
 280   XCHAR_TABLE (down)->extras[0] = up;
 281
 282   for (i = 0; i < 128; i++)
 283     {
 284       int c = ((i >= 'A' && i <= 'Z') ? i + ('a' - 'A')
 285                : ((i >= 'a' && i <= 'z') ? i + ('A' - 'a')
 286                   : i));;
 287       CHAR_TABLE_SET (up, i, make_number (c));
 288     }
 289
 290   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 291 }
 292
 293 void
 294 syms_of_casetab ()
 295 {
 296   Qcase_table_p = intern ("case-table-p");
 297   staticpro (&Qcase_table_p);
 298
 299   staticpro (&Vascii_canon_table);
 300   staticpro (&Vascii_downcase_table);
 301   staticpro (&Vascii_eqv_table);
 302   staticpro (&Vascii_upcase_table);
 303
 304   defsubr (&Scase_table_p);
 305   defsubr (&Scurrent_case_table);
 306   defsubr (&Sstandard_case_table);
 307   defsubr (&Sset_case_table);
 308   defsubr (&Sset_standard_case_table);
 309 }