Duck Typing

duck_typing.rb

def make_a_sound(obj)
  obj.sound!
end

def catch_make_a_sound(obj)
  return obj.sound! if obj.respond_to? sound!
  "#{obj.name} does not make a sound!!"
end

class Mouse
  attr_accessor :name
end

class Dog
  attr_accessor :name

  def sound!
    "woof!!"
  end
end

class Cat
  attr_accessor :name

  def sound!
    "meow!!"
  end
end

class Duck
  attr_accessor :name

  def sound!
    "quack!!"
  end
end