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_ */