ruby - 理解使用“::”的 Ruby 代码

Question

有时我会看到这样的代码：

module Elite

    module App
        def app
            'run app'
        end
    end

    module Base
        def base
            'base module'
        end
    end

    class Application
        include Elite::Base #Include variant A
        include ::Elite::App #Include variant B

        def initialize(str=nil) 
            puts "Initialized with #{str}"
            puts "Is respond to base?: #{base if self.respond_to?(:base)}"
            puts "Is respond to app?: #{app if self.respond_to?(:app)}"

        end
    end

    class Store < ::Elite::Application

        def initialize(str=nil)
            super #Goes to Application init
        end
    end
end

elite = Elite::Store.new(:hello)

但我不明白class Store < ::Elite::Applicationandclass Store < Elite::Application或include Elite::Baseand之间有什么不同include ::Elite::App 只是编码风格，还是有什么不同？

类/模块之前做什么::？:: 类/模块的干净命名空间（模块名称）？因为class Store < Application有效，但这不起作用：class Store < ::Application. 请告诉我有什么区别...谢谢！

Answer 1

'::' 是基本（全局）范围运算符。

所以'::Application'引用了基础应用程序，而'Application'引用了当前范围内的应用程序。

例如

class Application # Class 1
end

class Smile
  class Application # Class 2
  end

  ::Application # references class 1
  Application # references class 2 (The application in my current scope)
end