use Tk ;

my($mw) = new MainWindow ;

my($closeSub) = sub {
	print "closing\n" ; 
	$mw->destroy  ;
} ;

$mw->protocol('WM_DELETE_WINDOW', $closeSub) ;

my($button) = $mw->Button(-command => $closeSub, -text => "Close")->pack ;

MainLoop ;