NAME
     yacc - an LALR(1) parser generator

SYNOPSIS
     yacc [-dlrtv] [-b file-prefix] [-p symbol-prefix] filename

DESCRIPTION
     Yacc reads the grammar specification in the file filename 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 following options are available:

     -b file-prefix
                   The -b option changes the prefix prepended to the output
                   file names to the string denoted by file-prefix. The de-
                   fault 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.  Any #line directives
                   specified by the user will be retained.

     -p symbol-prefix
                   The -p option changes the prefix prepended to yacc-generat-
                   ed symbols to the string denoted by symbol-prefix. The de-
                   fault 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
     The following environment variable is referenced by yacc:

     TMPDIR  If the environment variable TMPDIR is set, the string denoted by
             TMPDIR will be used as the name of the directory where the tempo-
             rary files are 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-ze-
     ro.  (All of these names depend on the -p flag in the obvious manner.
     Note that other symbols, such as YYDEBUG and yylex, are not affected by
     the -p flag.)

FILES


     y.code.c
     y.tab.c
     y.tab.h
     y.output
     /tmp/yacc.aXXXXXX
     /tmp/yacc.tXXXXXX
     /tmp/yacc.uXXXXXX

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 ALSO
     yyfix(1)

STANDARDS
     The yacc utility conforms to IEEE Std1003.2 (``POSIX'').