Cool tricks with AT codes

We can invoke other kinds of widgets too, like this volume slider

              Volume => sub {
                  my $r = shift;
                  $r->percent_slider(
                      title    => 'Volume',
                      value    => $xmms->get_main_volume,
                      steps    => 10,
                      callback => sub {
                          $xmms->set_main_volume( shift )
                      },
                  );
                  return;
	      },