my $mw = MainWindow->new;
    my $text;

    $mw->Label(
        -text => "Enter password:"
    )->pack();

    $mw->Entry(
        -textvariable => \$text
    )->pack();

    $mw->Button(
        -text => "Submit",
        -command => sub {exit}
    )->pack();

    MainLoop;