yacc Command
  
  
  Purpose
  
  Generates an LR(1) parsing program from input consisting of a
  context-free grammar specification.
  
   Syntax
  
  yacc [  -bPrefix ] [  -d ] [  -l ] [  -NnNumber ] [  -NmNumber ]
  [  -pPath ] [  -s ] [  -t ] [  -v ] Grammar
  
  Description
  
  The yacc command converts a context-free grammar specification
  into a set  of  tables  for  a  simple automaton that executes an
  LR(1) parsing algorithm.  The grammar can be ambiguous; specified
  precedence rules are used to break ambiguities.
  
  You must compile the output file, y.tab.c, with a C Language com-
  piler to produce a yyparse function.  This function must be load-
  ed with the yylex lexical analyzer, as well as the main subrou-
  tine and the yyerror error-handling subroutine (you must provide
  these subroutines).  The lex command is useful for creating lexi-
  cal analyzers usable by the yyparse subroutine.
  
  You can compile the yacc-generated C file (y.tab.c) with the
  -DYACC_MSG option to include code necessary to use the Message
  Facility.    When  you  use this option during compilation, error
  messages generated by the yyparse subroutine and the YYBACKUP
  macro are extracted from the yacc_user.cat catalog.
  
  This allows you to receive error messages in languages other than
  English in non-English locales.    If the catalog cannot be found
  or opened, the yyparse and YYBACKUP subroutines display the de-
  fault English messages.
  
  The yacc command is affected by the LANG, LC_ALL, LC_CTYPE, and
  LC_MESSAGES environment variables.
  
  Flags
  
  -bPrefix	Use Prefix instead of y as the prefix for all output
  file names.  The code file y.tab.c, the header file y.tab.h
  (created when -d is specified), and the description file y.output
  (created when -v is specified), are changed to Prefix.tab.c,
  Prefix.tab.h, and Prefix.output, respectively.
  
  -d	Produces the file y.tab.h.  This contains the #define state-
  ments that associate the yacc-assigned token codes with your to-
  ken names.  This allows source files other than y.tab.c to access
  the token codes by including this header file.
  
  -l	Does not include any #line constructs in y.tab.c.  Use this
  only after the grammar and associated actions are fully debugged.
  
  -NnNumber	Changes the size of the token and nonterminal names ar-
  ray to Number.  The default value is 8000.  Valid values are only
  those greater than 8000.
  
  -NmNumber	Changes the size of the memory states array to Number.
  Default value is 40,000.  Valid  values  are  only  those greater
  than 40,000.
  
  -pPath	Uses the parser prototype specified by the Path instead of
  the default /usr/lib/yaccpar file.  The yyparse, yylex, and
  yyerror subroutine names are affected by this flag, as are the
  variable names yylval, yychar, and yydebug.  Other subroutine and
  external variable names may be also be affected by this flag.
  
  -s	Breaks the yyparse function into several smaller functions.
  Since its size is somewhat proportional  to  that of the grammar,
  it is possible for the yyparse function to become too large to
  compile, optimize, or execute efficiently.
  
  -t	Compiles run-time debugging code.  By default, this code is
  not included when y.tab.c is compiled.  However, the run-time de-
  bugging code is under the control of YYDEBUG, a global variable
  for the cc command preprocessor.  If YYDEBUG has a nonzero value,
  the C compiler (cc) includes the debugging code, regardless of
  whether the -t flag is used.  YYDEBUG should have a value of 0 if
  you  don't  want  the  debugging  code  included by the compiler.
  Without compiling this code, the yyparse subroutine will have a
  faster operating speed.
  
  -v	Prepares the file y.output.  It contains a readable descrip-
  tion of the parsing tables and a report on conflicts generated by
  grammar ambiguities.
  
  Exit Status
  
  This command returns the following exit values:
  
  0	Successful completion.
  
  >0	An error occurred.
  
  Examples
  
  1.	The following command:
  
  yacc grammar.y
  
  draws yacc rules from the grammar.y file, and places the output
  in y.tab.c.
  
  2.	The following command:
  
  yacc -d grammar.y
  
  functions as Example 1, but it also produces the y.tab.h file
  which would contain C-style #define statements for each of the
  tokens defined in the grammar.y file.
  
  Files
  
  y.output	A readable description of the parsing tables and a re-
  port on conflicts generated by grammar ambiguities.
  
  y.tab.c	Output file.
  
  y.tab.h	Definitions for token names.
  
  yacc.tmp	Temporary file.
  
  yacc.debug	Temporary file.
  
  yacc.acts	Temporary file.
  
  /usr/ccs/lib/yaccpar	Parser prototype for C programs.
  
  /usr/ccs/lib/liby.a	Runtime library.
  
  Implementation Specifics
  
  This command is part of Application Development Toolkit in Base
  Application Development Toolkit.
  
  Related Information
  
   Creating an Input Language with the lex and yacc Commands in AIX
  Version 3.2 General Programming Concepts.
  
  The  lex command.
  
  The  Example program for the lex and yacc programs in AIX Version
  3.2 General Programming Concepts.