Object model results

object_model.rb

# Classes are containers for methods
# Objects are containers for instance variables
# scopes are containers for local variables
#   and execute in the context of an object
# When you call a method on an object
#   it looks it up in the class
#   if it doesn't find it there
#   it continues looking it up in the chain of superclasses
# Module is a container for methods
#   When you include it into a class
#   It makes a new class with the module's methods
#   and sticks that into the inheritance hierarchy
# When you define a method on an object
#   It makes a new class called the singleton class
#   and defines the method there
#   and puts that into the inheritance hierarchy

class Address
  def initialize(line1, line2)
    @line1 = line1
    @line2 = line2
  end

  def line1
    @line1
  end

  def line2
    @line2
  end
end

class User
  def initialize(name)
    @name = name
  end

  def name=(new_name)
    @name = new_name
  end

  def name
    @name
  end
end

module HasAddress
  def address=(new_address)
    @address = new_address
  end

  def address
    @address
  end
end

class UserWithAddress < User
  include HasAddress
  
  def initialize(name, address)
    @address = address
    super(name)
  end
end

class User
  def self.default
    new("John Doe")
  end
end


address = Address.new '1801 S. Bell St', 'Arlington, VA 22020'
user    = UserWithAddress.new 'Josh', address
user.address.line1 # => "1801 S. Bell St"

User.default.name # => "John Doe"