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YACC(1)                                                                YACC(1)


Yacc - an LALR(1) parser generator


yacc [ -dglrtv ] [ -b file_prefix ] [ -p symbol_prefix ] filename


Yacc reads the grammar specification in the file filename and generates an LALR(1) parser for it. The parsers consist of a set of LALR(1) parsing tables and a driver routine written in the C programming lan- guage. Yacc normally writes the parse tables and the driver routine to the file 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 default prefix is the character y. -d The -d option causes the header file to be writ- ten. -g The -g option causes a graphical description of the gen- erated LALR(1) parser to be written to the file in graphviz format, ready to be processed by dot(1). -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 direc- tives specified by the user will be retained. -o output_file specify the filename for the parser file. If this option is not given, the output filename is the file prefix con- catenated with the file suffix, e.g., This overrides the -p option. -p symbol_prefix The -p option changes the prefix prepended to yacc-gener- ated 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 -t The -t option changes the preprocessor directives gener- ated by yacc so that debugging statements will be incor- porated 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. -V print the version number to the standard output.


If there are rules that are never reduced, the number of such rules is reported on standard error. If there are any LALR(1) conflicts, the number of conflicts is reported on standard error. 4.3 Berkeley Distribution July 15, 1990 YACC(1)