module CollectiveIdea
  module Recursable
    module Tree
      def self_and_descendants
        list = []
        recurse do |c, recurse_here|
          list << c
          recurse_here.call
        end
        list
      end
    
      def descendants
        self_and_descendants - [self]
      end
    
      def self_and_ancestors
        [self] | ancestors
      end
    end
  end
end