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143 lines
5.2 KiB
C
143 lines
5.2 KiB
C
/* Prepare the LALR and GLR parser tables.
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Copyright (C) 2002, 2004, 2009-2015, 2018-2020 Free Software
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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 TABLES_H_
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# define TABLES_H_
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# include "state.h"
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/* The parser tables consist of these tables.
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YYTRANSLATE = vector mapping yylex's token numbers into bison's
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token numbers.
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YYTNAME = vector of string-names indexed by bison token number.
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YYTOKNUM = vector of yylex token numbers corresponding to entries
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in YYTNAME.
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YYRLINE = vector of line-numbers of all rules. For yydebug
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printouts.
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YYRHS = vector of items of all rules. This is exactly what RITEMS
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contains. For yydebug and for semantic parser.
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YYPRHS[R] = index in YYRHS of first item for rule R.
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YYR1[R] = symbol number of symbol that rule R derives.
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YYR2[R] = number of symbols composing right hand side of rule R.
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YYSTOS[S] = the symbol number of the symbol that leads to state S.
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YYFINAL = the state number of the termination state.
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YYTABLE = a vector filled with portions for different uses, found
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via YYPACT and YYPGOTO, described below.
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YYLAST ( = high) the number of the last element of YYTABLE, i.e.,
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sizeof (YYTABLE) - 1.
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YYCHECK = a vector indexed in parallel with YYTABLE. It indicates,
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in a roundabout way, the bounds of the portion you are trying to
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examine.
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Suppose that the portion of YYTABLE starts at index P and the index
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to be examined within the portion is I. Then if YYCHECK[P+I] != I,
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I is outside the bounds of what is actually allocated, and the
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default (from YYDEFACT or YYDEFGOTO) should be used. Otherwise,
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YYTABLE[P+I] should be used.
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YYDEFACT[S] = default reduction number in state s. Performed when
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YYTABLE doesn't specify something else to do. Zero means the default
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is an error.
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YYDEFGOTO[I] = default state to go to after a reduction of a rule
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that generates variable NTOKENS + I, except when YYTABLE specifies
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something else to do.
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YYPACT[S] = index in YYTABLE of the portion describing state S.
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The lookahead token's number, I, is used to index that portion of
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YYTABLE to find out what action to perform.
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If YYPACT[S] == YYPACT_NINF, if YYPACT[S] + I is outside the bounds
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of YYTABLE (from 0 to YYLAST), or I is outside the bounds for portion
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S (that is, YYCHECK[YYPACT[S] + I] != I), then the default action
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(that is, YYDEFACT[S]) should be used instead of YYTABLE. Otherwise,
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the value YYTABLE[YYPACT[S] + I] should be used even if
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YYPACT[S] < 0.
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If the value in YYTABLE is positive, we shift the token and go to
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that state.
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If the value is negative, it is minus a rule number to reduce by.
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If the value is YYTABLE_NINF, it's a syntax error.
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YYPGOTO[I] = the index in YYTABLE of the portion describing what to
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do after reducing a rule that derives variable I + NTOKENS. This
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portion is indexed by the parser state number, S, as of before the
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text for this nonterminal was read.
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If YYPGOTO[I] + S is outside the bounds of YYTABLE (from 0 to YYLAST)
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or if S is outside the bounds of the portion for I (that is,
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YYCHECK[YYPGOTO[I] + S] != S), then the default state (that is,
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YYDEFGOTO[I]) should be used instead of YYTABLE. Otherwise,
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YYTABLE[YYPGOTO[I] + S] is the state to go to even if YYPGOTO[I] < 0.
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When the above YYPACT, YYPGOTO, and YYCHECK tests determine that a
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value from YYTABLE should be used, that value is never zero, so it is
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useless to check for zero. When those tests indicate that the value
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from YYDEFACT or YYDEFGOTO should be used instead, the value from
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YYTABLE *might* be zero, which, as a consequence of the way in which
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the tables are constructed, also happens to indicate that YYDEFACT or
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YYDEFGOTO should be used. However, the YYTABLE value cannot be
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trusted when the YYDEFACT or YYDEFGOTO value should be used. In
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summary, forget about zero values in YYTABLE.
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*/
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extern int nvectors;
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typedef int base_number;
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extern base_number *base;
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/* A distinguished value of BASE, negative infinite. During the
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computation equals to BASE_MINIMUM, later mapped to BASE_NINF to
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keep parser tables small. */
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extern base_number base_ninf;
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extern int *conflict_table;
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extern int *conflict_list;
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extern int conflict_list_cnt;
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extern base_number *table;
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extern base_number *check;
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/* The value used in TABLE to denote explicit syntax errors
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(%nonassoc), a negative infinite. */
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extern base_number table_ninf;
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extern state_number *yydefgoto;
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extern rule_number *yydefact;
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extern int high;
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void tables_generate (void);
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void tables_free (void);
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#endif /* !TABLES_H_ */
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