python - 在python中处理递归错误回溯

Question

我正在努力在Python中实现小型编程语言，而该语言的执行基本上包括对名为execute的函数的递归调用。我已经实现了自己的错误处理，但是为了进行该错误处理，我需要捕获一些异常并将它们作为我自己的类型抛出，从而导致代码如下所示:

def execute(...):
    try:
        try:
            # do stuff
        except IndexError:
            raise MyIndexError()
    except MyErrorBase as e:
        raise MyErrorBase(e, newTracebackLevel) # add traceback level for this depth

我真的很讨厌嵌套的try块...有什么办法可以解决这个问题？

Answer 1

如果确实要执行此操作，请尝试在基本异常类型和新异常类型之间创建映射:

exceptionMap = {
   IndexError: MyIndexError,
   # ...
}

def execute(...):
    try:
        # do stuff
    except tuple(exceptionMap) as e:
        raise exceptionMap[type(e)](e, newTracebackLevel)

例:

In [33]: exceptionMap = {IndexError: RuntimeError}

In [34]: a = []

In [35]: try:
    ...:     a[1]
    ...: except tuple(exceptionMap) as e:
    ...:     raise exceptionMap[type(e)](str(e))

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-35-bc6fdfc44fbe> in <module>()
      2     a[1]
      3 except tuple(exceptionMap) as e:
----> 4     raise exceptionMap[type(e)](str(e))
      5
      6

RuntimeError: list index out of range