Generics and Constants

main.cr

module Something(T)
  macro extended
    alias Somethingelse = ({{ @type.id }} | Nil)
    WHATEVER = [] of Somethingelse

    def self.add(item : Somethingelse)
      WHATEVER.push(item)
    end

  end

end

class Rimas
  extend Something(Rimas)

  def self.runit
    r = Rimas.new
    add(r)
    WHATEVER.each do |item|
      if !item.nil?
        item.doit
      end
    end
  end

  def doit
    puts "doit"
  end
end

Rimas.runit