Rails中的模型名称空间问题 [英] Model namespace issue in rails

问题描述

我在Rails 3.1中的名称空间有问题.我有一堂课，叫它一堂.

I am having an issue with namespaces in Rails 3.1. I have a class, let's call it a.

#/app/models/a.rb
class a
  #some methods
  def self.method_from_a
    #does things
  end
end

但是我还有另一个在不同名称空间中具有相同名称的类.

But I also have another class that has the same name in a different namespace.

#/app/models/b/a.rb
class b::a
  def method
    return a.method_from_a
  end
end

当我打电话给b :: a.method时，我得到了:

When I call b::a.method though I get:

NameError: uninitialized constant b::a::a

我确信这是一个简单的解决方案，我只是想念它.

I am sure it is a simple solution, I am just missing it.

推荐答案

在a前面加上:::

class b::a
  def method
    return ::a.method_from_a
  end
end

对此(即作用域运算符)也进行了此处的解释. :

This, (i.e. the scope operator) is also explained here:

在类或模块中定义的常量可以不经修饰地访问 类或模块内的任何地方.在课程或模块之外，他们 可以使用无前缀的范围运算符::'' prefixed by an expression that returns the appropriate class or module object. Constants defined outside any class or module may be accessed unadorned or by using the scope operator ::''进行访问.

Constants defined within a class or module may be accessed unadorned anywhere within the class or module. Outside the class or module, they may be accessed using the scope operator, ::'' prefixed by an expression that returns the appropriate class or module object. Constants defined outside any class or module may be accessed unadorned or by using the scope operator::'' with no prefix.

顺便说一句，在Ruby中，类名应以大写字母开头.

By the way, in Ruby class names should start with an upper case letter.

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