[bison.git] / src / lalr.h

/* Compute look-ahead criteria for bison,
   Copyright 1984, 1986, 1989, 2000, 2002 Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   Bison is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   Bison is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bison; see the file COPYING.  If not, write to
   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef LALR_H_
# define LALR_H_

#include "bitset.h"

/* Import the definition of CORE, SHIFTS and REDUCTIONS. */
# include "state.h"


/* Compute how to make the finite state machine deterministic; find
   which rules need lookahead in each state, and which lookahead
   tokens they accept.  */

void lalr PARAMS ((void));


/* lalr() builds these data structures. */

/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
   which accepts a variable (a nonterminal).

   FROM_STATE[T] -- state number which a transition leads from.
   TO_STATE[T] -- state number it leads to.

   All the transitions that accept a particular variable are grouped
   together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and
   TO_STATE of the first of them.  */

extern short *goto_map;
extern short *from_state;
extern short *to_state;

/* LARULENO is a vector which records the rules that need lookahead in
   various states.  The elements of LARULENO that apply to state S are
   those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1.  Each element
   of LARULENO is a rule number.

   If LR is the length of LAruleno, then a number from 0 to LR-1 can
   specify both a rule and a state where the rule might be applied.
   */

extern short *LAruleno;

/* LA is a lr by ntokens matrix of bits.  LA[l, i] is 1 if the rule
   LAruleno[l] is applicable in the appropriate state when the next
   token is symbol i.  If LA[l, i] and LA[l, j] are both 1 for i != j,
   it is a conflict.  */

extern bitset *LA;


/* All the states, indexed by the state number.  */
extern state_t **states;

extern int tokensetsize;

#endif /* !LALR_H_ */
Commit	Line	Data
720d742f	1	/* Compute look-ahead criteria for bison,
602bbf31	2	Copyright 1984, 1986, 1989, 2000, 2002 Free Software Foundation, Inc.
720d742f AD	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
602bbf31	24	#include "bitset.h"
a70083a3 AD	25
	26	/* Import the definition of CORE, SHIFTS and REDUCTIONS. */
	27	# include "state.h"
	28
	29
720d742f AD	30	/* Compute how to make the finite state machine deterministic; find
	31	which rules need lookahead in each state, and which lookahead
	32	tokens they accept. */
	33
	34	void lalr PARAMS ((void));
	35
	36
	37	/* lalr() builds these data structures. */
	38
43591cec	39	/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
720d742f AD	40	which accepts a variable (a nonterminal).
720d742f AD	41
43591cec AD	42	FROM_STATE[T] -- state number which a transition leads from.
	43	TO_STATE[T] -- state number it leads to.
	44
	45	All the transitions that accept a particular variable are grouped
	46	together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and
	47	TO_STATE of the first of them. */
720d742f AD	48
	49	extern short *goto_map;
	50	extern short *from_state;
	51	extern short *to_state;
	52
720d742f AD	53	/* LARULENO is a vector which records the rules that need lookahead in
	54	various states. The elements of LARULENO that apply to state S are
	55	those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1. Each element
	56	of LARULENO is a rule number.
	57
	58	If LR is the length of LAruleno, then a number from 0 to LR-1 can
	59	specify both a rule and a state where the rule might be applied.
	60	*/
	61
	62	extern short *LAruleno;
	63
	64	/* LA is a lr by ntokens matrix of bits. LA[l, i] is 1 if the rule
	65	LAruleno[l] is applicable in the appropriate state when the next
	66	token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j,
	67	it is a conflict. */
	68
602bbf31	69	extern bitset *LA;
720d742f AD	70
720d742f AD	71
f693ad14	72	/* All the states, indexed by the state number. */
29e88316	73	extern state_t **states;
9703cc49	74
720d742f	75	extern int tokensetsize;
720d742f AD	76
720d742f AD	77	#endif /* !LALR_H_ */