Singleton 類的繼承

Created: November-22, 2018

子類化也是子類 Singleton 類

class Example
end

Example.singleton_class #=> #<Class:Example>

def Example.foo
  :example
end

class SubExample < Example
end

SubExample.foo #=> :example

SubExample.singleton_class.superclass #=> #<Class:Example>

擴充套件或包含模組不會擴充套件 Singleton 類

module ExampleModule
end

def ExampleModule.foo
  :foo
end

class Example
  extend ExampleModule
  include ExampleModule
end

Example.foo #=> NoMethodError: undefined method