package Foo;

our $count = 0;

sub new {
   my $class = (ref($_[0]) ? ref(shift) : shift);

   $count++;
 
   return bless({ @_ }, $class);
}

package Bar;

our @ISA = ('Foo');

sub new {
   my $self = SUPER::new(@_);

   #Anything unique to this class can now be applied to the object...


   return $self;
}