demonstration of order that ruby methods are look up

look_up_methods_order.rb

module W
  def foo
    "- Mixed in method defined by W\n" + super
  end
end

module X
  def foo
    "- Mixed in method defined by X\n" + super
  end
end

module Y
  def foo
    "- Mixed in method defined by Y\n" + super
  end
end

module Z
  def foo
    "- Mixed in method defined by Z\n" + super
  end
end

class A
  def foo
    "- Instance method defined by A\n"
  end
end

class B < A
  include W
  include X

  def foo
    "- Instance method defined by B\n" + super
  end
end

object = B.new
object.extend(Y)
object.extend(Z)

def object.foo
  "- Method defined directly on an instance of B\n" + super
end

puts object.foo


- Method defined directly on an instance of B
- Mixed in method defined by Z
- Mixed in method defined by Y
- Instance method defined by B
- Mixed in method defined by X
- Mixed in method defined by W
- Instance method defined by A



1. Methods defined in the object's singleton class (i.e. the object itself)
2. Modules mixed into the singleton class in reverse order of inclusion
3. Methods defined by the object's class
4. Modules included into the object's class in reverse order of inclusion
5. Methods defined by the object's superclass.