Tricks of the Wizards

`Filter::Simple`

The easy way to do filtering is with Filter::Simple
We'll build a module that understands rot13-scrambled source code
- Rot13:

     abcdefghijklm nopqrstuvwxyz ABCDEFGHIJKLM NOPQRSTUVWXYZ
     nopqrstuvwxyz abcdefghijklm NOPQRSTUVWXYZ ABCDEFGHIJKLM

Our test program looks like this:

        use Rot13;

        zl $f = "Uryyb, jbeyq\a";
        $| = 1;
        sbe (0 .. yratgu($f)) {
          cevag fhofge($f, $_, 1);
          fyrrc 1 vs enaq() < .5;
        }

        no Rot13;

        print "All done!\n";

And in fact this works as written, and produces the output:

        Hello, world
        All done!