AFAIK,一旦发现异常,抓住它引发的上下文为时已晚。如果捕获异常的新的呼叫,您可以使用evil.rb的Binding.of_caller抓住呼叫范围,并做
eval("local_variables.collect { |l| [l, eval(l)] }", Binding.of_caller)
但是,这是一个相当大的黑客。正确的答案可能是扩展Ruby以允许对调用堆栈进行一些检查。我不确定是否有一些新的Ruby实现会允许这样做,但是我确实记得对Binding.of_caller的反对,因为它会使优化变得困难得多。
(说实话,我不明白这个反弹:只要翻译记录有关执行的优化足够的信息,Binding.of_caller应能正常工作,但也许慢)
更新
好吧,我想通了。 Longish代码如下:
class Foo < Exception
attr_reader :call_binding
def initialize
# Find the calling location
expected_file, expected_line = caller(1).first.split(':')[0,2]
expected_line = expected_line.to_i
return_count = 5 # If we see more than 5 returns, stop tracing
# Start tracing until we see our caller.
set_trace_func(proc do |event, file, line, id, binding, kls|
if file == expected_file && line == expected_line
# Found it: Save the binding and stop tracing
@call_binding = binding
set_trace_func(nil)
end
if event == :return
# Seen too many returns, give up. :-(
set_trace_func(nil) if (return_count -= 1) <= 0
end
end)
end
end
class Hello
def a
x = 10
y = 20
raise Foo
end
end
class World
def b
Hello.new.a
end
end
begin World.new.b
rescue Foo => e
b = e.call_binding
puts eval("local_variables.collect {|l| [l, eval(l)]}", b).inspect
end
嘿,图像链接已损坏。 – alanjds 2017-11-01 16:17:26