my $window = for_obj(Gtk::Window->new("toplevel"), sub {
    $_->signal_connect(delete => sub { Gtk->exit(0) });
    $_->set_title("Test");
    $_->border_width(15);
    $_->add(for_obj(Gtk::Button->new("Quit") ,sub {
        $_->signal_connect(clicked => sub { Gtk->exit(0) });
        $_->show;
        $_
    });
    $_->show;
});

##</code><code>##

my $window = do {
    local $_ = Gtk::Window->new('toplevel');

    $_->signal_connect(delete => sub { Gtk->exit(0) });
    $_->set_title('Test');
    $_->border_width(15);
    $_->add( do {
        local $_ = Gtk::Button->new('Quit');
        $_->signal_connect(clicked => sub { Gtk->exit(0) });
        $_->show;
        $_;
    } );
    $_->show;

    $_;
};