For example, a simplified version of the Animal class might be defined as follows:

package Animal;
use Class::MethodMaker
  new_with_init => 'new',
  get_set => [-eiffel => [qw(color height name age)]],
  abstract => [qw(sound)],
;
sub init {
  my $self = shift;
  $self->set_color($self->default_color);
}
sub named {
  my $self = shift->new;
  $self->set_name(shift);
  $self;
}
sub speak {
  my $self = shift;
  print $self->name, " goes ", $self->sound, "\n";
}
sub eat {
  my $self = shift;
  my $food = shift;
  print $self->name, " eats $food\n";
}
sub default_color {
  "brown";
}

The getters and setters for the four instance attributes (name, height, color, and age) are defined automatically, using the method color to get the color and set_color to set the color. (The eiffel flag says "do it the way the Eiffel language does it," which is the way it should be done here.) The messy blessing step is now hidden behind a simple new method. The initial color is defined as the default color, as before, because the init method is automatically called from new.

However, you can still call Horse->named('Mr. Ed') because it immediately calls the new routine as well.

sub generic_name {
  my $either = shift;
  ref $either ? $either->name : "an unnamed $either";
}
sub speak {
  my $either = shift;
  print $either->generic_name, " goes ", $either->sound, "\n";
}
sub eat {
  my $either = shift;
  my $food = shift;
  print $either->generic_name, " eats $food\n";
}