use Tk;
my $mw = new MainWindow; 
my $label = $mw -> Label(-text=>"Hello World") -> pack();
my $button = $mw -> Button(-text => "Quit");
$button->bind('<ButtonPress-1>' => \&myexit);
$button->pack;
MainLoop;
$button->eventGenerate('<ButtonPress-1>');

sub myexit
{
exit;
}