Eastward HO!

eastward_ho.rb

class Person
  attr_reader :address

  def display_address(template = Template.new)
    address.display(template)
    self
  end
end

class Address
  def display(template)
    address_data_structure = to_data(template.address_structure)
    template.display_address(address_data_structure)
    self
  end

  private

  def to_data(structure)
    structure.keys.inject({}) { |hash, key| hash.store(key, send(key)) }
  end
end

class Template
  def address_structure
    Hash[[ :street, :city, :state, :postal_code ].map { |k| [k, nil] }]
  end
  
  def display_address(address_data_structure)
    # do stuff to format address_data_structure...
    STOUT.puts formatted_address
    self
  end
end