1yacc(1) User Commands yacc(1)
2
6 yacc - yet another compiler-compiler
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9 yacc [-dltVv] [-b file_prefix] [-Q [y | n]]
10 [-P parser] [-p sym_prefix] file
11
14 The yacc command converts a context-free grammar into a set of tables
15 for a simple automaton that executes an LALR(1) parsing algorithm. The
16 grammar can be ambiguous. Specified precedence rules are used to break
17 ambiguities.
18 The output file, y.tab.c, must be compiled by the C compiler to produce
21 a function yyparse(). This program must be loaded with the lexical ana‐
22 lyzer program, yylex(), as well as main() and yyerror(), an error han‐
23 dling routine. These routines must be supplied by the user. The lex(1)
24 command is useful for creating lexical analyzers usable by yacc.
25
27 The following options are supported:
28 -b file_prefix Uses file_prefix instead of y as the prefix for all
30 output files. The code file y.tab.c, the header file
31 y.tab.h (created when -d is specified), and the
32 description file y.output (created when -v is speci‐
33 fied), is changed to file_prefix.tab.c, file_pre‐
34 fix.tab.h, and file_prefix.output, respectively.
35 -d Generates the file y.tab.h with the #define state‐
38 ments that associate the yacc user-assigned "token
39 codes" with the user-declared "token names". This
40 association allows source files other than y.tab.c to
41 access the token codes.
42 -l Specifies that the code produced in y.tab.c does not
45 contain any #line constructs. This option should only
46 be used after the grammar and the associated actions
47 are fully debugged.
48 -p sym_prefix Uses sym_prefix instead of yy as the prefix for all
51 external names produced by yacc. The names affected
52 include the functions yyparse(), yylex() and yyer‐
53 ror(), and the variables yylval, yychar and yydebug.
54 (In the remainder of this section, the six symbols
55 cited are referenced using their default names only
56 as a notational convenience.) Local names can also be
57 affected by the -p option. However, the -p option
58 does not affect #define symbols generated by yacc.
59 -P parser Allows you to specify the parser of your choice
62 instead of /usr/share/lib/ccs/yaccpar. For example,
63 you can specify:
64 example% yacc -P ~/myparser parser.y
66 -Q[y|n] The -Qy option puts the version stamping information
71 in y.tab.c. This allows you to know what version of
72 yacc built the file. The -Qn option (the default)
73 writes no version information.
74 -t Compiles runtime debugging code by default. Runtime
77 debugging code is always generated in y.tab.c under
78 conditional compilation control. By default, this
79 code is not included when y.tab.c is compiled.
80 Whether or not the -t option is used, the runtime
81 debugging code is under the control of YYDEBUG , a
82 preprocessor symbol. If YYDEBUG has a non-zero value,
83 then the debugging code is included. If its value is
84 0, then the code is not included. The size and execu‐
85 tion time of a program produced without the runtime
86 debugging code is smaller and slightly faster.
87 -v Prepares the file y.output, which contains a descrip‐
90 tion of the parsing tables and a report on conflicts
91 generated by ambiguities in the grammar.
92 -V Prints on the standard error output the version
95 information for yacc.
96
99 The following operand is required:
100 file A path name of a file containing instructions for which a
102 parser is to be created.
103
106 Example 1 Accessing the yacc Library
107 Access to the yacc library is obtained with library search operands to
110 cc. To use the yacc library main:
111 example% cc y.tab.c -ly
114 Both the lex library and the yacc library contain main. To access the
119 yacc main:
120 example% cc y.tab.c lex.yy.c -ly -ll
123 This ensures that the yacc library is searched first, so that its main
128 is used.
129 The historical yacc libraries have contained two simple functions that
133 are normally coded by the application programmer. These library func‐
134 tions are similar to the following code:
135 #include <locale.h>
138 int main(void)
139 {
140 extern int yyparse();
141 setlocale(LC_ALL, "");
143 /* If the following parser is one created by lex, the
145 application must be careful to ensure that LC_CTYPE
146 and LC_COLLATE are set to the POSIX locale. */
147 (void) yyparse();
148 return (0);
149 }
150 #include <stdio.h>
152 int yyerror(const char *msg)
154 {
155 (void) fprintf(stderr, "%s\n", msg);
156 return (0);
157 }
158
161 See environ(5) for descriptions of the following environment variables
162 that affect the execution of yacc: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
163 and NLSPATH.
164 yacc can handle characters from EUC primary and supplementary codesets
167 as one-token symbols. EUC codes can only be single character quoted
168 terminal symbols. yacc expects yylex() to return a wide character
169 (wchar_t) value for these one-token symbols.
170
172 The following exit values are returned:
173 0 Successful completion.
175 >0 An error occurred.
178
181 y.output state transitions of the generated parser
182 y.tab.c source code of the generated parser
185 y.tab.h header file for the generated parser
188 yacc.acts temporary file
191 yacc.debug temporary file
194 yacc.tmp temporary file
197 yaccpar parser prototype for C programs
200
203 See attributes(5) for descriptions of the following attributes:
204 ┌─────────────────────────────┬─────────────────────────────┐
209 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
210 ├─────────────────────────────┼─────────────────────────────┤
211 │Availability │SUNWbtool │
212 ├─────────────────────────────┼─────────────────────────────┤
213 │Interface Stability │Committed │
214 ├─────────────────────────────┼─────────────────────────────┤
215 │Standard │See standards(5). │
216 └─────────────────────────────┴─────────────────────────────┘
217
219 lex(1), attributes(5), environ(5), standards(5)
220
222 The number of reduce-reduce and shift-reduce conflicts is reported on
223 the standard error output. A more detailed report is found in the
224 y.output file. Similarly, if some rules are not reachable from the
225 start symbol, this instance is also reported.
226
228 Because file names are fixed, at most one yacc process can be active in
229 a given directory at a given time.
230 Users are encouraged to avoid using $ as part of any identifier name.
233SunOS 5.11 24 Aug 2009 yacc(1)