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1 /* Definitions for symtab.c and callers, part of Bison.
2 
3    Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2004, 2005, 2006
4    Free Software Foundation, Inc.
5 
6    This file is part of Bison, the GNU Compiler Compiler.
7 
8    Bison 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 2, or (at your option)
11    any later version.
12 
13    Bison 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 Bison; see the file COPYING.  If not, write to
20    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21    Boston, MA 02110-1301, USA.  */
22 
23 #ifndef SYMTAB_H_
24 # define SYMTAB_H_
25 
26 # include "assoc.h"
27 # include "location.h"
28 # include "uniqstr.h"
29 
30 /*----------.
31 | Symbols.  |
32 `----------*/
33 
34 /* Symbol classes.  */
35 typedef enum
36 {
37   unknown_sym,
38   token_sym,		/* terminal symbol */
39   nterm_sym		/* non-terminal */
40 } symbol_class;
41 
42 
43 /* Internal token numbers. */
44 typedef int symbol_number;
45 #define SYMBOL_NUMBER_MAXIMUM INT_MAX
46 
47 
48 typedef struct symbol symbol;
49 
50 /* When extending this structure, be sure to complete
51    symbol_check_alias_consistency.  */
52 struct symbol
53 {
54   /* The key, name of the symbol.  */
55   uniqstr tag;
56   /* The location of its first occurrence.  */
57   location location;
58 
59   /* Its %type and associated printer and destructor.  */
60   uniqstr type_name;
61   location type_location;
62 
63   /* Does not own the memory. */
64   const char *destructor;
65   location destructor_location;
66 
67   /* Does not own the memory. */
68   const char *printer;
69   location printer_location;
70 
71   symbol_number number;
72   location prec_location;
73   int prec;
74   assoc assoc;
75   int user_token_number;
76 
77   /* Points to the other in the identifier-symbol pair for an alias.
78      Special value USER_NUMBER_ALIAS in the identifier half of the
79      identifier-symbol pair for an alias.  */
80   symbol *alias;
81   symbol_class class;
82   bool declared;
83 };
84 
85 /* Undefined user number.  */
86 #define USER_NUMBER_UNDEFINED -1
87 
88 /* `symbol->user_token_number == USER_NUMBER_ALIAS' means this symbol
89    *has* (not is) a string literal alias.  For instance, `%token foo
90    "foo"' has `"foo"' numbered regularly, and `foo' numbered as
91    USER_NUMBER_ALIAS.  */
92 #define USER_NUMBER_ALIAS -9991
93 
94 /* Undefined internal token number.  */
95 #define NUMBER_UNDEFINED (-1)
96 
97 /* Print a symbol (for debugging). */
98 void symbol_print (symbol *s, FILE *f);
99 
100 /* Fetch (or create) the symbol associated to KEY.  */
101 symbol *symbol_get (const char *key, location loc);
102 
103 /* Generate a dummy nonterminal, whose name cannot conflict with the
104    user's names.  */
105 symbol *dummy_symbol_get (location loc);
106 
107 /* Declare the new symbol SYM.  Make it an alias of SYMVAL.  */
108 void symbol_make_alias (symbol *sym, symbol *symval, location loc);
109 
110 /* Set the TYPE_NAME associated with SYM.  Do nothing if passed 0 as
111    TYPE_NAME.  */
112 void symbol_type_set (symbol *sym, uniqstr type_name, location loc);
113 
114 /* Set the DESTRUCTOR associated with SYM.  */
115 void symbol_destructor_set (symbol *sym, const char *destructor, location loc);
116 
117 /* Set the PRINTER associated with SYM.  */
118 void symbol_printer_set (symbol *sym, const char *printer, location loc);
119 
120 /* Set the PRECEDENCE associated with SYM.  Ensure that SYMBOL is a
121    terminal.  Do nothing if invoked with UNDEF_ASSOC as ASSOC.  */
122 void symbol_precedence_set (symbol *sym, int prec, assoc a, location loc);
123 
124 /* Set the CLASS associated with SYM.  */
125 void symbol_class_set (symbol *sym, symbol_class class, location loc,
126 		       bool declaring);
127 
128 /* Set the USER_TOKEN_NUMBER associated with SYM.  */
129 void symbol_user_token_number_set (symbol *sym, int user_number, location loc);
130 
131 
132 /* Distinguished symbols.  AXIOM is the real start symbol, that used
133    by the automaton.  STARTSYMBOL is the one specified by the user.
134    */
135 extern symbol *errtoken;
136 extern symbol *undeftoken;
137 extern symbol *endtoken;
138 extern symbol *accept;
139 extern symbol *startsymbol;
140 extern location startsymbol_location;
141 
142 
143 /*---------------.
144 | Symbol table.  |
145 `---------------*/
146 
147 
148 /* Create the symbol table.  */
149 void symbols_new (void);
150 
151 /* Free all the memory allocated for symbols.  */
152 void symbols_free (void);
153 
154 /* Check that all the symbols are defined.  Report any undefined
155    symbols and consider them nonterminals.  */
156 void symbols_check_defined (void);
157 
158 /* Perform various sanity checks, assign symbol numbers, and set up
159    TOKEN_TRANSLATIONS.  */
160 void symbols_pack (void);
161 
162 #endif /* !SYMTAB_H_ */
163