yacc(1)                        DG/UX 5.4R3.00                        yacc(1)


NAME
       yacc - yet another compiler-compiler

SYNOPSIS
       yacc [-vVdlt] [-Q[y|n]] file

DESCRIPTION
       The yacc command converts a context-free grammar into a set of tables
       for a simple automaton that executes an LALR(1) parsing algorithm.
       The grammar may be ambiguous; specified precedence rules are used to
       break ambiguities.

       The output file, y.tab.c, must be compiled by the C compiler to
       produce a program yyparse.  This program must be loaded with the
       lexical analyzer program, yylex, as well as main and yyerror, an
       error handling routine.  These routines must be supplied by the user;
       the lex(1) command is useful for creating lexical analyzers usable by
       yacc.


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


       -d       Generates the file y.tab.h with the #define statements that
                associate the yacc-assigned ``token codes'' with the
                user-declared ``token names.''  This association allows
                source files other than y.tab.c to access the token codes.


       -l       Specifies that the code produced in y.tab.c will not contain
                any #line constructs.  This option should only be used after
                the grammar and the associated actions are fully debugged.

       -Q[y|n]  The -Qy option puts the version stamping information in
                y.tab.c.  This allows you to know what version of yacc built
                the file.  The -Qn option (the default) writes no version
                information.

       -t       Compiles runtime debugging code by default.  Runtime
                debugging code is always generated in y.tab.c under
                conditional compilation control.  By default, this code is
                not included when y.tab.c is compiled.  Whether or not the
                -t option is used, the runtime debugging code is under the
                control of YYDEBUG, a preprocessor symbol.  If YYDEBUG has a
                non-zero value, then the debugging code is included.  If its
                value is zero, then the code will not be included.  The size
                and execution time of a program produced without the runtime
                debugging code will be smaller and slightly faster.

       -V       Prints on the standard error output the version information
                for yacc.




Licensed material--property of copyright holder(s)                         1

yacc(1)                        DG/UX 5.4R3.00                        yacc(1)


   International Features
       yacc can process characters from supplementary code sets as well as
       ASCII characters.

       Characters from supplementary code sets can be specified in comments
       which exist in declarations, rules, and programs.

       Characters from supplementary code sets can be specified in strings
       which exist in actions in rules and in programs.

       Character strings from supplementary code sets can be defined as
       tokens.

FILES
       y.output
       y.tab.c
       y.tab.h             defines for token names
       yacc.tmp,
       yacc.debug, yacc.acts
                           temporary files
       LIBDIR/yaccpar      parser prototype for C programs
       LIBDIR              usually /usr/ccs/lib
SEE ALSO
       lex(1).
       The ``yacc'' chapter in the Programmer's Guide: ANSI C and
       Programming Support Tools.
DIAGNOSTICS
       The number of reduce-reduce and shift-reduce conflicts is reported on
       the standard error output; a more detailed report is found in the
       y.output file.  Similarly, if some rules are not reachable from the
       start symbol, this instance is also reported.
NOTES
       Because file names are fixed, at most one yacc process can be active
       in a given directory at a given time.























Licensed material--property of copyright holder(s)                         2