-/* Compute look-ahead criteria for bison,
- Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc.
+/* Compute lookahead criteria for bison,
+
+ Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007 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
+ This program 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.
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
- Bison is distributed in the hope that it will be useful,
+ This program 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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef LALR_H_
# define LALR_H_
+# include <bitset.h>
+# include <bitsetv.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).
+/* Import the definition of RULE_T. */
+# include "gram.h"
- FROM_STATE[T] -- state number which a transition leads from.
- TO_STATE[T] -- state number it leads to.
+/* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
+# include "state.h"
- 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;
+/** Build the LALR(1) automaton.
-/* 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.
+ Compute how to make the finite state machine deterministic; find
+ which rules need lookahead in each state, and which lookahead
+ tokens they accept.
- 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.
- */
+ Builds:
+ - #goto_map
+ - #from_state
+ - #to_state
+*/
+void lalr (void);
-extern short *LAruleno;
+/**
+ * Update state numbers recorded in #goto_map, #from_state, and #to_state such
+ * that:
+ * - \c nstates_old is the old number of states.
+ * - Where \c i is the old state number, <tt>old_to_new[i]</tt> is either:
+ * - \c nstates_old if state \c i is removed because it is unreachable.
+ * Thus, remove all goto entries involving this state.
+ * - The new state number.
+ */
+void lalr_update_state_numbers (state_number old_to_new[],
+ state_number nstates_old);
-/* 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 unsigned *LA;
-#define LA(Rule) (LA + (Rule) * tokensetsize)
+/** Release the information related to lookahead tokens.
+ Can be performed once the action tables are computed. */
+void lalr_free (void);
-/* A structure decorating a state, with additional information. */
-typedef struct state_s
-{
- /* A state. */
- core *state;
- /* Its accessing symbol. */
- short accessing_symbol;
+typedef size_t goto_number;
+# define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
- shifts *shift_table;
- reductions *reduction_table;
+/** Index into #from_state and #to_state.
- /* Nonzero if no lookahead is needed to decide what to do in state
- S. */
- char consistent;
+ 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 goto_number *goto_map;
- short lookaheads;
-} state_t;
+/** State number which a transition leads from. */
+extern state_number *from_state;
-/* All the decorated states, indexed by the state number. Warning:
- there is a state_TABLE in LR0.c, but it is different and static.
- */
-extern state_t *state_table;
+/** State number it leads to. */
+extern state_number *to_state;
-extern int tokensetsize;
-/* The number of lookaheads. */
-extern size_t nlookaheads;
#endif /* !LALR_H_ */
projects / bison.git / blobdiff