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yacc


NAME
     yacc - yet another compiler-compiler

SYNOPSIS
     /usr/ccs/bin/yacc [-dltVv] [-b file_prefix] [ -Q

      [y | n] ] [-P parser] [-p sym_prefix] 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 function yyparse(). This program must be loaded
     with the lexical  analyzer  program,  yylex(),  as  well  as
     main()  and yyerror(), an error handling routine. These rou-
     tines must be supplied by the user. The  lex(1)  command  is
     useful for creating lexical analyzers usable by yacc.

OPTIONS
     The following options are supported:

     -b file_prefix  Uses file_prefix instead of y as the  prefix
                     for all output files. 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),
                     will   be   changed   to  file_prefix.tab.c,
                     file_prefix.tab.h,  and  file_prefix.output,
                     respectively.



     -d              Generates the file y.tab.h with the  #define
                     statements  that  associate  the  yacc user-
                     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.



     -p sym_prefix   Uses sym_prefix instead of yy as the  prefix
                     for all external names produced by yacc. The
                     names   affected   include   the   functions
                     yyparse(),  yylex()  and  yyerror(), and the
                     variables yylval, yychar  and  yydebug.  (In
                     the  remainder of this section, the six sym-
                     bols  cited  are  referenced   using   their
                     default  names only as a notational conveni-
                     ence.) Local names may also be  affected  by
                     the  -p  option. However, the -p option does
                     not  affect  #define  symbols  generated  by
                     yacc.



     -P parser       Allows you to specify  the  parser  of  your
                     choice  instead of /usr/ccs/bin/yaccpar. For
                     example, you can specify:


                     example% yacc -P ~/myparser parser.y



     -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 ver-
                     sion 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 YYDE-
                     BUG  , a preprocessor symbol. If YYDEBUG has
                     a non-zero value, then the debugging code is
                     included.  If  its value is 0, then the code
                     will not be included. The size and execution
                     time  of a program produced without the run-
                     time debugging  code  will  be  smaller  and
                     slightly faster.



     -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.



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



OPERANDS
     The following operand is required:

     file     A path name of a file containing  instructions  for
              which a parser is to be created.



EXAMPLES
     Example 1: Accessing the yacc library

     Access to the yacc library is obtained with  library  search
     operands to cc. To use the yacc library main:

     example% cc y.tab.c -ly

     Both the lex library and the yacc library contain  main.  To
     access the yacc main:

     example% cc y.tab.c lex.yy.c -ly -ll

     This ensures that the yacc library  is  searched  first,  so
     that its main is used.

     The historical yacc  libraries  have  contained  two  simple
     functions  that  are  normally coded by the application pro-
     grammer. These library functions are similar to the  follow-
     ing code:


     #include <locale.h>
     int main(void)
     {
             extern int yyparse();

             setlocale(LC_ALL, "");

             /* If the following parser is one created by lex, the
                application must be careful to ensure that LC_CTYPE
                and LC_COLLATE are set to the POSIX locale.  */
             (void) yyparse();
             return (0);
     }
     #include <stdio.h>

     int yyerror(const char *msg)
     {
             (void) fprintf(stderr, "%s\n", msg);
             return (0);
     }



ENVIRONMENT VARIABLES
     See environ(5) for descriptions of the following environment
     variables  that  affect the execution of yacc: LANG, LC_ALL,
     LC_CTYPE, LC_MESSAGES, and NLSPATH.

     yacc can handle characters from EUC primary  and  supplemen-
     tary  codesets  as  one-token symbols. EUC codes may only be
     single  character  quoted  terminal  symbols.  yacc  expects
     yylex() to return a wide character (wchar_t) value for these
     one-token symbols.

EXIT STATUS
     The following exit values are returned:

     0        Successful completion.



     >0       An error occurred.



FILES
     y.output        state transitions of the generated parser



     y.tab.c         source code of the generated parser



     y.tab.h         header file for the generated parser



     yacc.acts       temporary file



     yacc.debug      temporary file


     yacc.tmp        temporary file



     yaccpar         parser prototype for C programs



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWbtool                   |
    |_____________________________|_____________________________|
    | Interface Stability         | Standard                    |
    |_____________________________|_____________________________|


SEE ALSO
     cc(1B), lex(1), attributes(5), environ(5), standards(5)

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.

     Users are encouraged to avoid using '$' as part of any iden-
     tifier name.










Man pages from Solaris 10 Update 8. See docs.sun.com and www.oracle.com for further documentation and Solaris information.
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