Getting a list of classes that include a module

Question

I have a mixin for which I would like to get a list of all the classes that have included it. In the mixin module, I did the following:

module MyModule
  def         


        

Answer 1

Actually, your module extension module works. The problem is in your test: when you created a random unnamed class with Class.new, you forgot to include MyModule. As a side note, you can take your read-only accessor for classes that include the module and use the helpful Module#attr_reader method.

Answer 2

You probably should use extend instead of include since former adds class level methods, while latter - instance level methods (why you have access to @classes).

Try this:

module MyModule
  extend ListIncludedClasses::ClassMethods
end

Answer 3

module MyMod; end

class A; include MyMod; end
class B < A; end
class C; end

ObjectSpace.each_object(Class).select { |c| c.included_modules.include? MyMod }
  #=> [B, A]