Stored Zoo data:
Llama - Feet:4 - Color:Tan
Camel - Feet:4 - Humps:2

##</code><code>##

#[pseudocode - will not compile]
foreach $line (<FILE>) {
   # Get $name and hash data from file
   # $name, $animalstats (hashref)
   my $newanimal = new Animal($name, $animalstats);
   push (@allanimals, $newanimal);
}

##</code><code>##

__DATA__
Llamas:
   Llama1 - data data data
   Llama2 - data data data
Camels:
   Camel1 - data data data
   Camel2 - data data data

__CODE__
# [pseudocode]
foreach (my $groupname = from_datafile()) {
  ## Llamas, Camels, the collections.
  unless (exists $allanimals{$groupname})
     ## Create a new collection if you don't already have one for that animal type.
     my $newcollection = new Animal::Collection($groupname);
     $allanimals{$groupname} = $newcollection;
  }
  my $collection = $allanimals{$groupname};
  # Now work with that collection. Add all your animals in that group.
  foreach $animal (animals_from_datafile()) {
    ## llama1, llama2, etc.
    $collection->add_animal(new Animal($animal, 
$animalstats);
  }
}

##</code><code>##

package Animal;
sub new (
  my $name = shift;
  my $data = shift;
  if($name == 'llama') {
    return new Animal::Llama($data);
  } elseif ($name == 'camel') {
    return new Animal::Camel($data);
  } else {
    warn "Unknown animal type\n";
    return new Animal::Generic($name, $data);
  }
}

##</code><code>##

foreach $type (keys $allanimals) {
  my $num_of_animals = $allanimals{$type}->count_collection(); # A method in Animal::Colelction
  foreach $animal ($allanimals{$type}->get_animals()) {
     ## Using methods defined by the Animal interface
     ## But implemented in the Animal::Llama, Animal::Camel, etc subclasses.
     my $name = $animal->get_name();
     $animal->feed();
  }
}