Ruby 元编程 编写代码的代码

1.Kernel#eval

2.0.0p247 :463 >   class String2.0.0p247 :464?>    def self.inherited(subclass)2.0.0p247 :465?>     puts "钩子函数"2.0.0p247 :466?>     end2.0.0p247 :467?>   end => nil 2.0.0p247 :468 > class MyString < String;end钩子函数 => nil 2.0.0p247 :469 >