#!/usr/bin/perl -w
use strict;
{ package Animal;
    sub named {			# Constructor of instance - Objects
	my $class = shift;		# first argument is class name
	die "already an object. $!"
	    if ref($class);		# only instances are references
	my $name = shift;		# 2nd arg is the object's identity
	my $self = {Name => $name, Color => $class->default_color}; 
	bless \$self, $class;		# create the object 
    }					
    sub set_name {
	my $object = shift;		# first argument s/b an instance
 	 my $name = shift;		# 2nd parm s/b the new animal name
	if (ref $object) {
	    $object->{Name} = $name;
	}
	else {die "It's a class variable, $!";}
    }
    sub name {
	my $self = shift;
	ref $self ? $self->{Name}
	: "Just another $self";		# Not an instance, hence no name
    }
}
{ package Horse;
    our @ISA = qw(Animal);
    sub default_color {"brown";}
}
my $tv_horse = Horse->named("Mr. Ed");
print $tv_horse->name, " is ",$tv_horse->name,"\n";
$tv_horse->set_name("Mister Ed");