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YACC(1)                     NetBSD Reference Manual                    YACC(1)


NAME

     yacc - an LALR(1) parser generator


SYNOPSIS

     yacc [-dlrtv] [-b prefix] [-o outputfile] [-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 prefix     The -b option changes the prefix prepended to the output
                   file names to the string denoted by 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 outputfile
                   The -o option specifies an explicit output file name should
                   be used instead of the default.

     -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.


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.


STANDARDS

     The yacc utility conforms to IEEE Std 1003.2 (``POSIX.2'').

NetBSD 1.5.2                     July 30, 1991                               2