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107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/* Compute lookahead criteria for bison,
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Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006-2007,
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2009-2015, 2018-2019 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef LALR_H_
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# define LALR_H_
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# include <bitset.h>
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# include <bitsetv.h>
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/* Import the definition of RULE_T. */
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# include "gram.h"
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/* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
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# include "state.h"
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/** Build the LALR(1) automaton.
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Find which rules need lookahead in each state, and which lookahead
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tokens they accept.
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Also builds:
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- #goto_map
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- #from_state
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- #to_state
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- #goto_follows
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*/
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void lalr (void);
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/**
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* Set #nLA and allocate all reduction lookahead sets. Normally invoked by
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* #lalr.
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*/
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void initialize_LA (void);
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/**
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* Build only:
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* - #goto_map
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* - #from_state
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* - #to_state
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* Normally invoked by #lalr.
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*/
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void set_goto_map (void);
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/**
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* Update state numbers recorded in #goto_map, #from_state, and #to_state such
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* that:
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* - \c nstates_old is the old number of states.
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* - Where \c i is the old state number, <tt>old_to_new[i]</tt> is either:
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* - \c nstates_old if state \c i is removed because it is unreachable.
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* Thus, remove all goto entries involving this state.
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* - The new state number.
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*/
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void lalr_update_state_numbers (state_number old_to_new[],
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state_number nstates_old);
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/** Release the information related to lookahead tokens.
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Can be performed once the action tables are computed. */
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void lalr_free (void);
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typedef size_t goto_number;
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# define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
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/** Index into #from_state and #to_state.
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All the transitions that accept a particular variable are grouped
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together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and
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TO_STATE of the first of them. */
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extern goto_number *goto_map;
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/** The size of #from_state and #to_state. */
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extern goto_number ngotos;
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/** State number which a transition leads from. */
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extern state_number *from_state;
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/** State number it leads to. */
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extern state_number *to_state;
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/** Map a state/symbol pair into its numeric representation. */
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goto_number map_goto (state_number s0, symbol_number sym);
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/* goto_follows[i] is the set of tokens following goto i. */
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extern bitsetv goto_follows;
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#endif /* !LALR_H_ */
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