在Ruby on Rails中定义命名空间模型的正确方法

Question

Just wondering what is the proper way to define a namespaced model in Rails. I've seen it defined in two ways. In most libraries they seem to be defined as such

module Fruit
  class Banana < ActiveRecord::Base
     ...
  end
end

whereas the Rails generator seems to prefer this

class Fruit::Banana < ActiveRecord::Base
  ...
end

They both obviously work but what is the difference? Which is preferred? Thanks!

Answer 1

They are not identical, the more verbose way will actually define the module, whereas the shorter way will expect it to be defined already.

class Fruit::Banana; end

That will throw a NameError . However if you do

module Fruit; end
class Fruit::Banana; end

it will not throw an error.

Answer 2

They're the same, but the "longer" version lets you add other stuff to the module. I prefer that since I'll often package multiple small things into a module that way.

Answer 3

它们是相同的，第二只是语法糖。