YACC(1)			 HP-UX 5.0		       YACC(1)

     NAME
	  yacc - yet another compiler-compiler

     SYNOPSIS
	  yacc [ -vdlt ] grammar

     HP-UX COMPATIBILITY
	  Level:    HP-UX/STANDARD

	  Origin:   System V

     DESCRIPTION
	  Yacc 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.  This is useful when you intend to compile y.tab.c
	  with the -g option for cdb, since  #line  constructs	should
	  not be used in file compiled with -g.	 (See cc(1), cdb(1)).

	  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
	  pre-processor 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
	  /usr/lib/yaccpar    parser prototype for C programs

     SEE ALSO
	  lex(1), malloc(3X).
	  LR Parsing by	 A.  V.	 Aho  and  S.  C.  Johnson,  Computing
	  Surveys, June, 1974.

	  YACC - Yet Another Compiler  Compiler	 in  HP-UX:   Selected
	  Articles.

     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.

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