是否有一个类似于继承的类的钩子只有在Ruby类定义后触发？

问题描述

#inherited 我想要的东西，只有在 end 语句关闭类声明后才会运行。

#inherited is called right after the class Foo statement. I want something that'll run only after the end statement that closes the class declaration.

例如我需要：

class Class
  def inherited m
    puts "In #inherited for #{m}"
  end
end

class Foo
  puts "In Foo"
end
puts "I really wanted to have #inherited tiggered here."


### Output:
# In #inherited for Foo
# In Foo
# I really wanted to have #inherited tiggered here.

有没有类似的东西？可以创建吗？

Does anything like that exist? Can it be created? Am I totally out of luck?

推荐答案

我迟到了，但我想我有一个答案（任何人访问这里） 。

I am late, but I think I have an answer (to anyone who visit here).

您可以跟踪，直到找到类定义的结尾。我在一个方法中调用了 after_inherited ：

You can trace until you find the end of the class definition. I did it in a method which I called after_inherited:

class Class
  def after_inherited child = nil, &blk
    line_class = nil
    set_trace_func(lambda do |event, file, line, id, binding, classname|
      unless line_class
        # save the line of the inherited class entry
        line_class = line if event == 'class'
      else
        # check the end of inherited class
        if line == line_class && event == 'end'
          # if so, turn off the trace and call the block
          set_trace_func nil
          blk.call child
        end
      end
    end)
  end
end

# testing...

class A
  def self.inherited(child)
    after_inherited do
      puts "XXX"
    end
  end
end

class B < A
  puts "YYY"
  # .... code here can include class << self, etc.
end

输出：

YYY
XXX

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