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)

Free Pascal                                        10 Jan 2000                                           plex(1)