src/lalr.h

   1 /* Compute look-ahead criteria for bison,
   2
   3    Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004 Free Software
   4    Foundation, Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    Bison is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    Bison is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with Bison; see the file COPYING.  If not, write to
  20    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #ifndef LALR_H_
  24 # define LALR_H_
  25
  26 # include <bitset.h>
  27 # include <bitsetv.h>
  28
  29 /* Import the definition of RULE_T. */
  30 # include "gram.h"
  31
  32 /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
  33 # include "state.h"
  34
  35 /* Compute how to make the finite state machine deterministic; find
  36    which rules need look-ahead in each state, and which look-ahead
  37    tokens they accept.  */
  38
  39 void lalr (void);
  40
  41 /* Release the information related to look-ahead tokens.  Can be performed
  42    once the action tables are computed.  */
  43
  44 void lalr_free (void);
  45
  46
  47 /* lalr() builds these data structures. */
  48
  49 /* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
  50    which accepts a variable (a nonterminal).
  51
  52    FROM_STATE[T] -- state number which a transition leads from.
  53    TO_STATE[T] -- state number it leads to.
  54
  55    All the transitions that accept a particular variable are grouped
  56    together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and
  57    TO_STATE of the first of them.  */
  58
  59 typedef size_t goto_number;
  60 # define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
  61
  62 extern goto_number *goto_map;
  63 extern state_number *from_state;
  64 extern state_number *to_state;
  65
  66
  67 #endif /* !LALR_H_ */