refactoring patterns

## Extract Class (http://refactoring.com/catalog/extractClass.html)

class Person
  attr_accessor :name, :office_area_code, :office_number

  def telephone_number
    [office_area_code, office_number].join('-')
  end
end

# Refactored

class Person
  attr_accessor :name

  def office_telephone
    @office_telephone ||= TelephoneNumber.new
  end

  def telephone_number
    office_telephone.telephone_number
  end

  class TelephoneNumber
    attr_accessor :area_code, :number
    
    def telephone_number
      [area_code.to_s, number].join('-')
    end
  end
end

--

p = Person.new

p.name = "Jordan"
p.office_telephone.area_code = 203
p.office_telephone.number    = "555-5555"

p.telephone_number #=> "203-555-5555"