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/* Compute lookahead criteria for bison,
Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006-2007,
2009-2015, 2018-2021 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
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 3 of the License, or
(at your option) any later version.
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 this program. If not, see <https://www.gnu.org/licenses/>. */
#ifndef LALR_H_
# define LALR_H_
# include <bitset.h>
# include <bitsetv.h>
/* Import the definition of RULE_T. */
# include "gram.h"
/* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
# include "state.h"
/** Build the LALR(1) automaton.
Find which rules need lookahead in each state, and which lookahead
tokens they accept.
Also builds:
- #goto_map
- #from_state
- #to_state
- #goto_follows
*/
void lalr (void);
/**
* Set #nLA and allocate all reduction lookahead sets. Normally invoked by
* #lalr.
*/
void initialize_LA (void);
/**
* Build only:
* - #goto_map
* - #from_state
* - #to_state
* Normally invoked by #lalr.
*/
void set_goto_map (void);
/**
* 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);
/** Release the information related to lookahead tokens.
Can be performed once the action tables are computed. */
void lalr_free (void);
typedef size_t goto_number;
# define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
/** Index into #from_state and #to_state.
All the transitions that accept a particular variable are grouped
together in FROM_STATE and TO_STATE, with indexes from GOTO_MAP[I -
NTOKENS] to GOTO_MAP[I - NTOKENS + 1] - 1 (including both). */
extern goto_number *goto_map;
/** The size of #from_state and #to_state. */
extern goto_number ngotos;
/** State number which a transition leads from. */
extern state_number *from_state;
/** State number it leads to. */
extern state_number *to_state;
/** The number of the goto from state SRC labeled with nterm SYM. */
goto_number map_goto (state_number src, symbol_number sym);
/* goto_follows[i] is the set of tokens following goto i. */
extern bitsetv goto_follows;
#endif /* !LALR_H_ */
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