YACC(1) OpenBSD Reference Manual YACC(1)NAMEyacc - an LALR(1) parser generator
SYNOPSISyacc [-dlrtv] [-b file_prefix] [-o output_file] [-p symbol_prefix] file
DESCRIPTIONyacc reads the grammar specification in file and generates an LR(1)
parser for it. The parsers consist of a set of LALR(1) parsing tables
and a driver routine written in the C programming language. yacc
normally writes the parse tables and the driver routine to the file
y.tab.c.
The options are as follows:
-b file_prefix
The -b option changes the prefix prepended to the output file
names to the string denoted by file_prefix. The default prefix
is the character y.
-d The -d option causes the header file y.tab.h to be written.
-l If the -l option is not specified, yacc will insert #line
directives in the generated code. The #line directives let the C
compiler relate errors in the generated code to the user's
original code. If the -l option is specified, yacc will not
insert the #line directives. #line directives specified by the
user will be retained.
-o output_file
The -o option specifies an explicit name for the parser's output
file name instead of the default. The names of the other output
files are constructed from output_file as described under the -d
and -v options.
-p symbol_prefix
The -p option changes the prefix prepended to yacc-generated
symbols to the string denoted by symbol_prefix. The default
prefix is the string yy.
-r The -r option causes yacc to produce separate files for code and
tables. The code file is named y.code.c, and the tables file is
named y.tab.c.
-t The -t option changes the preprocessor directives generated by
yacc so that debugging statements will be incorporated in the
compiled code.
-v The -v option causes a human-readable description of the
generated parser to be written to the file y.output.
ENVIRONMENT
TMPDIR Name of directory where temporary files are to be created.
TABLES
The names of the tables generated by this version of yacc are ``yylhs'',
``yylen'', ``yydefred'', ``yydgoto'', ``yysindex'', ``yyrindex'',
``yygindex'', ``yytable'', and ``yycheck''. Two additional tables,
``yyname'' and ``yyrule'', are created if YYDEBUG is defined and non-
zero.
FILES
y.code.c
y.tab.c
y.tab.h
y.output
/tmp/yacc.aXXXXXXXXXX
/tmp/yacc.tXXXXXXXXXX
/tmp/yacc.uXXXXXXXXXX
EXIT STATUS
The yacc utility exits 0 on success, and >0 if an error occurs.
DIAGNOSTICS
If there are rules that are never reduced, the number of such rules is
written to the standard error. If there are any LALR(1) conflicts, the
number of conflicts is also written to the standard error.
SEE ALSOyyfix(1)STANDARDS
The yacc utility is compliant with the IEEE Std 1003.1-2008 (``POSIX'')
specification, though its presence is optional.
The flags [-or] are extensions to that specification.
HISTORY
Yacc was originally developed at AT&T by Stephen C. Johnson.
Berkeley Yacc was originally developed using PCC on a VAX with the intent
of being as compatible as possible with AT&T Yacc. Much is owed to the
unflagging efforts of Keith Bostic. His badgering kept me working on
Yacc long after I was ready to quit.
Berkeley Yacc is based on the excellent algorithm for computing LALR(1)
lookaheads developed by Tom Pennello and Frank DeRemer. The algorithm is
described in their almost impenetrable article in TOPLAS 4,4.
Finally, much credit must go to those who pointed out deficiencies of
earlier releases. Among the most prolific contributors were Benson I.
Margulies, Dave Gentzel, Antoine Verheijen, Peter S. Housel, Dale Smith,
Ozan Yigit, John Campbell, Bill Sommerfeld, Paul Hilfinger, Gary
Bridgewater, Dave Bakken, Dan Lanciani, Richard Sargent, and Parag Patel.
AUTHORS
The yacc utility was written by Robert Corbett.
OpenBSD 4.9 October 18, 2010 OpenBSD 4.9
