How to inherit from NilClass or how to simulate similar function

Question

I just want to use Null Object Design Pattern, but I found I can inherit from NilClass.

I can write a method \"nil?\" and return false but what if user write code be

Answer 1

Instead of inheriting from NilClass I do the following

class NullObject < BasicObject
  include ::Singleton

  def method_missing(method, *args, &block)
    if nil.respond_to? method
      nil.send method, *args, &block
    else
      self
    end
  end
end

This gives you any custom method that have been monkey patched onto NilClass (such as ActiveSupport's blank? and nil?). You can also of course add custom null object behaviors, or change method_missing to handle other calls differently (this one returns the NullObject for chaining, but you could return nil for example).