需要在 rails3 的自定义模块中使用 `memoize`

Question

我在 lib 文件夹中有一个 module。我在其中创建了一个 InstanceMethods 模块。

require 'memoist'
extend Memoist
module MyStudentMethods
  def self.included base
    base.send :include, InstanceMethods
  end

  module InstanceMethods
    def find_student(user_id)
      self.student.find{|student| student.user_id == user_id }
    end
    memoize :find_student
  end
end

我在 model 中使用这个 module。

require_dependency 'my_student_methods'

class Student < ActiveRecord::Base
  # previously I was using memoize like below commented out code
  # require 'memoist'
  # extend Memoist
  include MyStudentMethods
end

但是当我启动 rails server 它时出现错误：

/home/Projects/school/lib/my_student_methods.rb:12:in `<module:InstanceMethods>': undefined method `memoize' for MyStudentMethods::InstanceMethods:Module (NoMethodError)

问题：如何memoize模块方法？

Answer 1

尝试将 extend Memoist 移动到您的模块中。像这样：

module InstanceMethods
  extend Memoist
  ...

Answer 2

module InstanceMethods
  extend Memoist
   ...