# cgi.pl

use strict;
use warnings;

@One::ISA = @Two::ISA = 'Zero';

{
  package Zero;
  use base 'CGI::' . shift;

  sub dispatch { shift->param ? 'Two' : 'One'; }

  sub render {
    print my $self = shift, "\n";
    print "$_: " . $self->param( $_ ) . "\n" for $self->param;
  }
}

@MY_Zero::ISA = 'Zero';

shift->activate;

__END__