Binding.of_caller (cont'd)

 5   tracer = lambda do |*args|
 6     type, context = args[0], args[4]
 7     if type == "return"
 8       count += 1
 9       if count == 2
10         set_trace_func(nil)
11         cc.call(eval("binding", context), nil)
12       end
13     elsif type != "line"
14       set_trace_func(nil)
15       cc.call(nil, lambda { raise(ArgumentError) })
16     end
17   end