YACC(1)                                                   YACC(1)



     NAME
          yacc - yet another compiler-compiler

     SYNOPSIS
          yacc [ -vdlt ] grammar

     DESCRIPTION
          The yacc command converts a context-free grammar into a set
          of tables for a simple automaton which executes an LR(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; lex(1) is useful for creating
          lexical analyzers usable by yacc.

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

          If the -d flag is used, the file y.tab.h is generated with
          the #define statements 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.

          If the -l flag is given, the code produced in y.tab.c will
          not contain any #line constructs.  This should only be used
          after the grammar and the associated actions are fully
          debugged.

          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.  However, when yacc's
          -t option is used, this debugging code will be compiled by
          default.  Independent of whether the -t option was 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.

     FILES
          y.output
          y.tab.c
          y.tab.h             defines for token names
          yacc.tmp,
          yacc.debug, yacc.acts    temporary files



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     YACC(1)                                                   YACC(1)



          /usr/lib/yaccpar    parser prototype for C programs

     SEE ALSO
          lex(1).
          Programmer's Guide.

     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 is also
          reported.

     CAVEAT
          Because file names are fixed, at most one yacc process can
          be active in a given directory at a given time.

     ORIGIN
          AT&T V.3




































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