1 /* Prepare the LALR and GLR parser tables. 2 3 Copyright (C) 2002, 2004, 2009-2012 Free Software Foundation, Inc. 4 5 This file is part of Bison, the GNU Compiler Compiler. 6 7 This program is free software: you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation, either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #ifndef TABLES_H_ 21 # define TABLES_H_ 22 23 # include "state.h" 24 25 /* The parser tables consist of these tables. 26 27 YYTRANSLATE = vector mapping yylex's token numbers into bison's 28 token numbers. 29 30 YYTNAME = vector of string-names indexed by bison token number. 31 32 YYTOKNUM = vector of yylex token numbers corresponding to entries 33 in YYTNAME. 34 35 YYRLINE = vector of line-numbers of all rules. For yydebug 36 printouts. 37 38 YYRHS = vector of items of all rules. This is exactly what RITEMS 39 contains. For yydebug and for semantic parser. 40 41 YYPRHS[R] = index in YYRHS of first item for rule R. 42 43 YYR1[R] = symbol number of symbol that rule R derives. 44 45 YYR2[R] = number of symbols composing right hand side of rule R. 46 47 YYSTOS[S] = the symbol number of the symbol that leads to state S. 48 49 YYFINAL = the state number of the termination state. 50 51 YYTABLE = a vector filled with portions for different uses, found 52 via YYPACT and YYPGOTO, described below. 53 54 YYLAST ( = high) the number of the last element of YYTABLE, i.e., 55 sizeof (YYTABLE) - 1. 56 57 YYCHECK = a vector indexed in parallel with YYTABLE. It indicates, 58 in a roundabout way, the bounds of the portion you are trying to 59 examine. 60 61 Suppose that the portion of YYTABLE starts at index P and the index 62 to be examined within the portion is I. Then if YYCHECK[P+I] != I, 63 I is outside the bounds of what is actually allocated, and the 64 default (from YYDEFACT or YYDEFGOTO) should be used. Otherwise, 65 YYTABLE[P+I] should be used. 66 67 YYDEFACT[S] = default reduction number in state s. Performed when 68 YYTABLE doesn't specify something else to do. Zero means the default 69 is an error. 70 71 YYDEFGOTO[I] = default state to go to after a reduction of a rule 72 that generates variable NTOKENS + I, except when YYTABLE specifies 73 something else to do. 74 75 YYPACT[S] = index in YYTABLE of the portion describing state S. 76 The lookahead token's number, I, is used to index that portion of 77 YYTABLE to find out what action to perform. 78 79 If YYPACT[S] == YYPACT_NINF, if YYPACT[S] + I is outside the bounds 80 of YYTABLE (from 0 to YYLAST), or I is outside the bounds for portion 81 S (that is, YYCHECK[YYPACT[S] + I] != I), then the default action 82 (that is, YYDEFACT[S]) should be used instead of YYTABLE. Otherwise, 83 the value YYTABLE[YYPACT[S] + I] should be used even if 84 YYPACT[S] < 0. 85 86 If the value in YYTABLE is positive, we shift the token and go to 87 that state. 88 89 If the value is negative, it is minus a rule number to reduce by. 90 91 If the value is YYTABLE_NINF, it's a syntax error. 92 93 YYPGOTO[I] = the index in YYTABLE of the portion describing what to 94 do after reducing a rule that derives variable I + NTOKENS. This 95 portion is indexed by the parser state number, S, as of before the 96 text for this nonterminal was read. 97 98 If YYPGOTO[I] + S is outside the bounds of YYTABLE (from 0 to YYLAST) 99 or if S is outside the bounds of the portion for I (that is, 100 YYCHECK[YYPGOTO[I] + S] != S), then the default state (that is, 101 YYDEFGOTO[I]) should be used instead of YYTABLE. Otherwise, 102 YYTABLE[YYPGOTO[I] + S] is the state to go to even if YYPGOTO[I] < 0. 103 104 When the above YYPACT, YYPGOTO, and YYCHECK tests determine that a 105 value from YYTABLE should be used, that value is never zero, so it is 106 useless to check for zero. When those tests indicate that the value 107 from YYDEFACT or YYDEFGOTO should be used instead, the value from 108 YYTABLE *might* be zero, which, as a consequence of the way in which 109 the tables are constructed, also happens to indicate that YYDEFACT or 110 YYDEFGOTO should be used. However, the YYTABLE value cannot be 111 trusted when the YYDEFACT or YYDEFGOTO value should be used. In 112 summary, forget about zero values in YYTABLE. 113 */ 114 115 extern int nvectors; 116 117 typedef int base_number; 118 extern base_number *base; 119 /* A distinguished value of BASE, negative infinite. During the 120 computation equals to BASE_MINIMUM, later mapped to BASE_NINF to 121 keep parser tables small. */ 122 extern base_number base_ninf; 123 124 extern unsigned int *conflict_table; 125 extern unsigned int *conflict_list; 126 extern int conflict_list_cnt; 127 128 extern base_number *table; 129 extern base_number *check; 130 /* The value used in TABLE to denote explicit syntax errors 131 (%nonassoc), a negative infinite. */ 132 extern base_number table_ninf; 133 134 extern state_number *yydefgoto; 135 extern rule_number *yydefact; 136 extern int high; 137 138 void tables_generate (void); 139 void tables_free (void); 140 141 #endif /* !TABLES_H_ */ 142