BasicObject中的binding.pry

Question

对于调试BasicObject的子类来说，pry将是非常棒的！

https://github.com/pry/pry说，pry有：“外来对象支持(BasicObject实例...”

但如何做到这一点呢？正如可以预期的那样，BasicObject不理解绑定。

 NameError:
   undefined local variable or method `binding' for #<C30Course:0xbefbc0c>

当调用method_missing时，将绑定发送到哪里？

Answer 1

您需要直接调用Kernel上的binding方法，如下所示：

[13] pry(main)> class O < BasicObject
              |   def hi
              |     x = 10
              |     ::Kernel.binding.pry
              |   end  
              | end  
=> nil
[14] pry(main)> O.new.hi

From: (pry) @ line 19 O#hi:

    17: def hi
    18:   x = 10
 => 19:   ::Kernel.binding.pry
    20: end

[1] pry(unknown)> x
=> 10
[2] pry(unknown)> self
=> #<O:0x3fd5310d04f8>

Answer 2

因为从BasicObject继承会给你一个Blank Slate (所有的撬动实例方法也被删除了)，所以你需要更多的手动操作。例如：

require 'pry'
class Test < BasicObject
  def test_method
    a = 1+1
    ::Pry.send(:binding).pry
    b = 2+2
  end
end
o = Test.new
p o.test_method

输出(打开的pry会话)：

☺  ruby hack.rb                                                            ruby-2.0.0-p0

From: .../quick_hacking/hack.rb @ line 5 Test#test_method:

    3: def test_method
    4:   a = 1+1
 => 5:   ::Pry.send(:binding).pry
    6:   b = 2+2
    7: end