package Car;

# class for storing information about a Car 

use warnings;
use strict;
use Carp;

sub new {
	my $class = shift;
	my $self = {
		ENGINE => undef, 
		BODY => undef,
		WHEELS => undef, # a list of wheels
	};
	my $closure = sub {
		my $field = shift;
		if (@_) { $self->{$field} = shift; }
		return $self->{$field};
	};
	bless ($closure,$class);
	return $closure;
}

# public accessors
sub engine { &{ $_[0] }("ENGINE", @_[1 .. $#_]) }
sub body   { &{ $_[0] }("BODY", @_[1 .. $#_]) }
sub wheels { &{ $_[0] }("WHEELS", @_[1 .. $#_]) }

sub accept {
	my $self = shift;
	my $visitor = shift;
	$visitor->visitCar($self);
	$self->engine->accept($visitor);
	$self->body->accept($visitor);
 	map { $_->accept($visitor) } @{$self->wheels};
}

1;