# an object is simply a closure with a hash of closures
sub make_object {
    my %msg;
    $msg{"add-msg"} = sub {
        my $m = shift();
        $msg{$m} = shift();
    };
    return sub {
        my $m = shift();
        return $msg{$m} ? 
            $msg{$m}->(@_) : print "unknown message\n";
    }
}