2

我正在阅读“Well Grounded Rubyist”一书，我对方法查找路径有疑问：

module M
  def report
    puts "'report' method in module M"
  end
end

module N
  def report
    puts "'report' method in module N"
  end
end

class C
  include M
  include N
  def report
    puts "'report' method in class C"
    puts "About to call super..."
    super
    puts "Back from super..."
  end
end

obj = C.new
obj.report

根据我的理解，obj.report 会输出：

'report' method in class C
About to call super...
'report' method in module N
Back from super...

但是，我很好奇是否可以通过在类 C 中绕过 N 的报告来调用 M 的报告方法。我知道如果我在模块 N 中添加“super”，它将调用 N 的报告，然后是 M 的报告，然后再放入“从超级回来......”但是有没有办法直接从 C 中做到这一点？

4

2 回答 2

3

您可以使用祖先反射：

class C
  def report
    my_ancestors = self.class.ancestors
    puts "my ancestors are: #{my_ancestors}"
    method = my_ancestors[2].instance_method(:report)
    method.bind(self).call
  end
end

C.new.report
=> my ancestors are: [C, N, M, Object, PP::ObjectMixin, Kernel, BasicObject]
=> 'report' method in module M
于 2013-01-29T01:05:42.660 回答
1

这可行，但我觉得必须有更好的方法来做到这一点，而无需将其更改为 self：

module M
   def self.report
      puts "'report' method in module M"
   end
end

Class C
include M
include N
def report
   puts "'report' method in class C"
   puts "About to call M.report..."
   M.report
   puts "About to call super..."
   super
    puts "Back from super..."
 end
 end

输出将是：

'report' method in class C
About to call M.report...
'report' method in module M
About to call super...
'report' method in module N
Back from super...
于 2013-01-29T00:57:49.833 回答