POODR: Chapter 4 - Creating Flexible Interfaces

Chapter_4.rb

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Law of Demeter
# set of coding rules that results in loosely coupled objects. It prohibits
# routing a message to a third object via a second object of a different type.
# Paraphrased:  "only talk to your immediate neighbors", "use only one dot"

class Trip

  def depart
    # "train wrecks"
    # if #tire or #rotate change, #depart may change
    # trip can't be reused unless it has access to a customer with a bicycle,
    # # that has a wheel, that has a tire. Too much context.
    customer.bicycle.wheel.tire
    customer.bicycle.wheel.rotate

    # This is reasonable.
    # hash.keys returns an Enumerable
    # sort returns an Enumerable
    # join returns a String
    hash.keys.sort.join(', ')
  end

end