use strict;
use warnings;

package Cow;
{
  sub speak { print ${$_[0]}, " says Moo\n" }
}

package Horse;
{
    sub speak { print ${$_[0]}, " says 'Hi, my name is Ed'\n" }
}

package Sheep;
{
    sub speak { print ${$_[0]}, " says Baaaah\n"  }
}

# mapping names to types
my %Pasture = ( Bessie => 'Cow',
                , Annie => 'Cow',
                , Joe => 'Horse'
                , Lily => 'Sheep'
                , James => 'Sheep'
               );

while (my ($name, $animal) = each(%Pasture)) {
  # assign a class to each name based on type
  my $oAnimal = bless(\do{my $anon=$name;}, $animal);

  # do processing that involves both name and type
  $oAnimal->speak();
}