Question

What is the difference between adding instance methods whith active concern and through the normal ruby def keyword on the module?

module MonsterConcern
  extend ActiveSupport::Concern

  included do
    def engage_rage
    end

    def chew_bones
    end
  end
end

and

module MonsterConcern
  def engage_rage
  end

  def chew_bones
  end
end

Answer 1

据我所知，如果你唯一感兴趣的是实例方法没有区别。

ActiveSupport::Concern的优点是能够定义类方法，并更好地处理一些讨厌的模块相互依赖性（与调用included块中的类方法有关）。