LEX(1)                  GENIX Programmer's Manual                  LEX(1)



      NAME
           lex - generator of lexical analysis programs

      SYNOPSIS
           lex [ -tvfn ] [ file ] ...

      DESCRIPTION
           Lex generates programs to be used in simple lexical analyis of text.
           The input files (standard input default) contain regular expressions
           to be searched for, and actions written in C  to  be  executed  when
           expressions are found.

           A C source program, `lex.yy.c' is generated, to be compiled thus:

                cc lex.yy.c -ll

           This program, when run, copies unrecognized portions of the input to
           the  output,  and  executes the associated C action for each regular
           expression that is recognized.

           The following lex program converts  upper  case  to  lower,  removes
           blanks  at  the end of lines, and replaces multiple blanks by single
           blanks.


                %%
                [A-Z] putchar(yytext[0]+'a'-'A');
                [ ]+$
                [ ]+  putchar(' ');

           The options have the following meanings.

           -t   Place the result on the standard  output  instead  of  in  file
                `lex.yy.c'.

           -v   Print  a  one-line  summary  of  statistics  of  the  generated
                analyzer.

           -n   Opposite of -v; -n is default.

           -f   `Faster'  compilation:  don't  bother  to  pack  the  resulting
                tables; limited to small programs.

      SEE ALSO
           yacc(1), sed(1)
           M. E. Lesk and E. Schmidt, LEX - Lexical Analyzer Generator









      Printed 11/16/83                                                        1