# YourApp.pm
package YourApp;
use base 'CGI::Application';
sub setup {
  my $self = shift;
  $self->start_mode('open');
  $self->mode_param('function');
  $self->run_modes(
    'open'   => 'do_open',
    'create' => 'do_create',
  );
}      

# yourapp.cgi
use YourApp;
my $app = YourApp->new;
$app->run;