YACC(1)                  DOMAIN/IX SYS5                   YACC(1)



NAME
     yacc - yet another compiler-compiler

USAGE
     yacc [ -vdlt ] grammar

DESCRIPTION
     Yacc converts a context-free grammar into a set of tables
     for a simple automaton that executes an LR parsing algo-
     rithm.  The grammar may be ambiguous; specified precedence
     rules are used to break ambiguities.

     The C compiler must compile the y.tab.c output file to pro-
     duce a yyparse program.  This program must be loaded with
     the lexical analyzer program, yylex, as well as main and
     yyerror, an error-handling routine.  You supply these rou-
     tines.  The lex(1) command can help create lexical analyzers
     for use by yacc.

OPTIONS
     -v        Prepare the y.output file, which contains a
               description of the parsing tables and a report on
               conflicts generated by ambiguities in the grammar.

     -d        Generate the y.tab.h file with the #define state-
               ments that associate the yacc-assigned token codes
               with the user-declared token names.  This allows
               source files other than y.tab.c to access the
               token codes.

     -l        Do not include any #line constructs in the code
               produced in the y.tab.c file. This should only be
               used after the grammar and the associated actions
               are fully debugged.

     -t        Compile runtime debugging code by default.  Run-
               time debugging code is always generated in y.tab.c
               under conditional compilation control.  Normally,
               this code is not included when y.tab.c is com-
               piled.  Regardless of whether or not this option
               is used, the runtime debugging code is always
               under the control of YYDEBUG, a preprocessor sym-
               bol.  If YYDEBUG has a non-zero value, then the
               debugging code is included.  If its value is zero,
               the code is not included.  The size and execution
               time of a program produced without the runtime
               debugging code is smaller and slightly faster.






Printed 12/4/86                                            YACC-1

YACC(1)                  DOMAIN/IX SYS5                   YACC(1)



CAUTIONS
     Because filenames are fixed, only one yacc process may be
     active in a given directory at a time.

FILES
     y.output

     y.tab.c

     y.tab.h             defines for token names

     yacc.tmp            temporary file

     yacc.debug          temporary file

     yacc.acts           temporary file

     /usr/lib/yaccpar    parser prototype for C programs

DIAGNOSTICS
     The number of reduce-reduce and shift-reduce conflicts is
     reported on the standard error output. (You can find a more
     detailed report in the y.output file.)  Similarly, if some
     rules cannot be reached from the start symbol, this is also
     reported.

RELATED INFORMATION
     lex(1), malloc(3C).

























YACC-2                                            Printed 12/4/86