Ruby on Rails，包括一个带参数的模块 [英] Ruby on Rails, including a module with arguments

问题描述

有没有办法在包含 ruby​​ 模块时使用参数?我有一个包含在许多类中的 Assetable 模块.我希望能够即时生成 attr_accessor.

Is there a way to use arguments when including a ruby module? I have a module Assetable which is included across many classes. I want to be able to generate attr_accessor's on the fly.

module Assetable
  extend ActiveSupport::Concern

  included do 
    (argument).times do |i| 
      attr_accessor "asset_#{i}".to_sym
      attr_accessible "asset_#{i}".to_sym
    end
  end
end 

推荐答案

在包含模块时无法传递参数.最好的下一件事是定义一个类方法，让您可以在之后创建您需要的内容:

There is no way of passing arguments when including the module. The best next thing would be to define a class method that lets you create what you need afterwards:

module Assetable
  extend ActiveSupport::Concern
  module ClassMethods
    def total_assets(number)
      number.times do |i|
        attr_accessor "asset_#{i}"
        attr_accessible "asset_#{i}"
      end
    end
  end
end

class C
  include Assetable
  total_assets 3
end

o = C.new
o.asset_2 = "Some value."
o.asset_2  #=> "Some value."

在关注中覆盖 included 方法时也要小心，因为它也被 ActiveSupport::Concern 使用.您应该在覆盖方法中调用 super 以确保正确初始化.

Also be careful when overriding the included method within a concern because it's also used by ActiveSupport::Concern. You should call super within the overriden method in order to ensure proper initialization.

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