src/lalr.h

   1 /* Compute look-ahead criteria for bison,
   2    Copyright (C) 1984, 1986, 1989, 2000, 2002 Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    Bison 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    Bison 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 Bison; 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 #ifndef LALR_H_
  22 # define LALR_H_
  23
  24 # include <bitset.h>
  25 # include <bitsetv.h>
  26
  27 /* Import the definition of RULE_T. */
  28 # include "gram.h"
  29
  30 /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
  31 # include "state.h"
  32
  33 /* Compute how to make the finite state machine deterministic; find
  34    which rules need lookahead in each state, and which lookahead
  35    tokens they accept.  */
  36
  37 void lalr (void);
  38
  39 /* Release the information related to lookaheads.  Can be performed
  40    once the action tables are computed.  */
  41
  42 void lalr_free (void);
  43
  44
  45 /* lalr() builds these data structures. */
  46
  47 /* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
  48    which accepts a variable (a nonterminal).
  49
  50    FROM_STATE[T] -- state number which a transition leads from.
  51    TO_STATE[T] -- state number it leads to.
  52
  53    All the transitions that accept a particular variable are grouped
  54    together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and
  55    TO_STATE of the first of them.  */
  56
  57 typedef short goto_number;
  58 # define GOTO_NUMBER_MAXIMUM SHRT_MAX
  59
  60 extern goto_number *goto_map;
  61 extern state_number *from_state;
  62 extern state_number *to_state;
  63
  64
  65 #endif /* !LALR_H_ */