#### a driver for the car
{ package Driver;
    sub new {
        my $class = shift;
        my $vars = {};
        $vars->{ALERTNESS} = 0;
        $vars->{STATE} = dstatenorm->new();
        bless ($vars, $class);
        return $vars; }

    sub alertness {
        my $vars = shift;
        my $state = $vars->{STATE};
        if(@_) { $vars->{ALERTNESS} = shift; }
        return $state->alertness( $vars->{ALERTNESS} ); }

    1; }

#### driver state normal
{ package dstatenorm;
    sub new {
        my $class = shift;
        my $vars = {};
        $vars->{"NAME"} = "Normal";
        bless ($vars, $class);
        return $vars; }

    sub alertness ($) {
        my $curAlertness = shift;
        return $curAlertness; }

    1; }