ruby - Ruby中如何获取给定单例(或本征)类对应的对象？

Question

假设如下代码:

class A
end

a = A.new

As = class << a
    self
end

# or:
# As = a.singleton_class

有什么方法可以从 As 得到 a 吗？

Answer 1

给你一个技巧:

class A
end

a = A.new

As = a.singleton_class

a2 = ObjectSpace.each_object.select{|obj| obj.singleton_class == As}.first

a2 == a # => true