Inherited Autoloaded Data Methods

But what about inheritance? Can we define our Employee class similarly? Yes, so long as we're careful enough.

Here's how to be careful: 

    package Employee;
    use Person;
    use strict;
    use vars qw(@ISA);
    @ISA = qw(Person);


    my %fields = (
	id          => undef,
	salary      => undef,
    );


    sub new {
	my $that  = shift;
	my $class = ref($that) || $that;
	my $self = bless $that->SUPER::new(), $class;
	my($element);
	foreach $element (keys %fields) {
	    $self->{_permitted}->{$element} = $fields{$element};
	}
	@{$self}{keys %fields} = values %fields;
	return $self;
    }

Once we've done this, we don't even need to have an AUTOLOAD function in the Employee package, because we'll grab Person's version of that via inheritance, and it will all work out just fine.