NAME

       plex - The Pascal Lex lexical analyzer generator.

USAGE

       lex [options] lex-file[.l] [output-file[.pas]]

OPTIONS

       -v     Verbose:  plex  generates a readable description of the generated lexical analyzer,
              written to lex-file with new extension .lst

       -o     Optimize: plex optimizes DFA tables to produce a minimal DFA.

DESCRIPTION

       plex is a program generator that is used to generate the Turbo Pascal source  code  for  a
       lexical  analyzer  subroutine  from  the  specification  of an input language by a regular
       expression grammar.

       plex parses the source grammar contained in lex-file (with default suffix .l)  and  writes
       the  constructed  lexical  analyzer  subroutine to the specified output-file (with default
       suffix .pas); if no output file is specified, output goes  to  lex-file  with  new  suffix
       .pas.  If  any errors are found during compilation, error messages are written to the list
       file (lex-file with new suffix .lst).

       The generated output file contains a lexical analyzer routine, yylex, implemented as:

                function yylex : Integer;

       This routine has to be called by your main program to execute the  lexical  analyzer.  The
       return  value of the yylex routine usually denotes the number of a token recognized by the
       lexical analyzer (see the return routine in the LexLib unit).  At  end-of-file  the  yylex
       routine normally returns 0.

       The  code  template for the yylex routine may be found in the yylex.cod file. This file is
       needed by TP Lex when it constructs the output file. It must  be  present  either  in  the
       current  directory  or  in  the  directory from which TP Lex was executed (TP Lex searches
       these directories in the indicated order). (NB: For the  Linux/Free  Pascal  version,  the
       code  template  is  searched  in  some  directory  defined  at compile-time instead of the
       execution path, usually /usr/lib/fpc/lexyacc.)

       The TP Lex library (LexLib) unit is  required  by  programs  using  Lex-generated  lexical
       analyzers;  you will therefore have to put an appropriate uses clause into your program or
       unit that contains the lexical analyzer routine. The LexLib  unit  also  provides  various
       useful utility routines; see the file lexlib.pas for further information.

MORE INFORMATION

       For more information, see the documentation that comes with plex and yacc.

AUTHOR

       Albert Graeff (<ag@muwiinfa.geschichte.uni-mainz.de>, <Dr.Graef@t-online.de>)

SEE ALSO

       ppc386(1) pyacc(1)