1 /* Prepare the LALR and GLR parser tables. 2 3 Copyright (C) 2002, 2004, 2009-2015, 2018-2021 Free Software 4 Foundation, Inc. 5 6 This file is part of Bison, the GNU Compiler Compiler. 7 8 This program is free software: you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation, either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 20 21 #ifndef TABLES_H_ 22 # define TABLES_H_ 23 24 # include "state.h" 25 26 /* The parser tables consist of these tables. 27 28 YYTRANSLATE = vector mapping yylex's token numbers into bison's 29 token numbers. 30 31 YYTNAME = vector of string-names indexed by bison token number. 32 33 YYTOKNUM = vector of yylex token numbers corresponding to entries 34 in YYTNAME. 35 36 YYRLINE = vector of line-numbers of all rules. For yydebug 37 printouts. 38 39 YYRHS = vector of items of all rules. This is exactly what RITEMS 40 contains. For yydebug and for semantic parser. 41 42 YYPRHS[R] = index in YYRHS of first item for rule R. 43 44 YYR1[R] = symbol number of symbol that rule R derives. 45 46 YYR2[R] = number of symbols composing right hand side of rule R. 47 48 YYSTOS[S] = the symbol number of the symbol that leads to state S. 49 50 YYFINAL = the state number of the termination state. 51 52 YYTABLE = a vector filled with portions for different uses, found 53 via YYPACT and YYPGOTO, described below. 54 55 YYLAST ( = high) the number of the last element of YYTABLE, i.e., 56 sizeof (YYTABLE) - 1. 57 58 YYCHECK = a vector indexed in parallel with YYTABLE. It indicates, 59 in a roundabout way, the bounds of the portion you are trying to 60 examine. 61 62 Suppose that the portion of YYTABLE starts at index P and the index 63 to be examined within the portion is I. Then if YYCHECK[P+I] != I, 64 I is outside the bounds of what is actually allocated, and the 65 default (from YYDEFACT or YYDEFGOTO) should be used. Otherwise, 66 YYTABLE[P+I] should be used. 67 68 YYDEFACT[S] = default reduction number in state s. Performed when 69 YYTABLE doesn't specify something else to do. Zero means the default 70 is an error. 71 72 YYDEFGOTO[I] = default state to go to after a reduction of a rule 73 that generates variable NTOKENS + I, except when YYTABLE specifies 74 something else to do. 75 76 YYPACT[S] = index in YYTABLE of the portion describing state S. 77 The lookahead token's number, I, is used to index that portion of 78 YYTABLE to find out what action to perform. 79 80 If YYPACT[S] == YYPACT_NINF, if YYPACT[S] + I is outside the bounds 81 of YYTABLE (from 0 to YYLAST), or I is outside the bounds for portion 82 S (that is, YYCHECK[YYPACT[S] + I] != I), then the default action 83 (that is, YYDEFACT[S]) should be used instead of YYTABLE. Otherwise, 84 the value YYTABLE[YYPACT[S] + I] should be used even if 85 YYPACT[S] < 0. 86 87 If the value in YYTABLE is positive, we shift the token and go to 88 that state. 89 90 If the value is negative, it is minus a rule number to reduce by. 91 92 If the value is YYTABLE_NINF, it's a syntax error. 93 94 YYPGOTO[I] = the index in YYTABLE of the portion describing what to 95 do after reducing a rule that derives variable I + NTOKENS. This 96 portion is indexed by the parser state number, S, as of before the 97 text for this nonterminal was read. 98 99 If YYPGOTO[I] + S is outside the bounds of YYTABLE (from 0 to YYLAST) 100 or if S is outside the bounds of the portion for I (that is, 101 YYCHECK[YYPGOTO[I] + S] != S), then the default state (that is, 102 YYDEFGOTO[I]) should be used instead of YYTABLE. Otherwise, 103 YYTABLE[YYPGOTO[I] + S] is the state to go to even if YYPGOTO[I] < 0. 104 105 When the above YYPACT, YYPGOTO, and YYCHECK tests determine that a 106 value from YYTABLE should be used, that value is never zero, so it is 107 useless to check for zero. When those tests indicate that the value 108 from YYDEFACT or YYDEFGOTO should be used instead, the value from 109 YYTABLE *might* be zero, which, as a consequence of the way in which 110 the tables are constructed, also happens to indicate that YYDEFACT or 111 YYDEFGOTO should be used. However, the YYTABLE value cannot be 112 trusted when the YYDEFACT or YYDEFGOTO value should be used. In 113 summary, forget about zero values in YYTABLE. 114 */ 115 116 extern int nvectors; 117 118 typedef int base_number; 119 extern base_number *base; 120 /* A distinguished value of BASE, negative infinite. During the 121 computation equals to BASE_MINIMUM, later mapped to BASE_NINF to 122 keep parser tables small. */ 123 extern base_number base_ninf; 124 125 extern int *conflict_table; 126 extern int *conflict_list; 127 extern int conflict_list_cnt; 128 129 extern base_number *table; 130 extern base_number *check; 131 /* The value used in TABLE to denote explicit syntax errors 132 (%nonassoc), a negative infinite. */ 133 extern base_number table_ninf; 134 135 extern state_number *yydefgoto; 136 extern rule_number *yydefact; 137 extern int high; 138 139 void tables_generate (void); 140 void tables_free (void); 141 142 #endif /* !TABLES_H_ */ 143