[Python-Dev] Chained Exceptions

[Guido van Rossum]

[Ka-Ping Yee]
> Suppose exceptions have an optional "context" attribute, which is
> set when the exception is raised in the context of handling another
> exception.  Thus:
> 
>     def a():
>         try:
>             raise AError
>         except:
>             raise BError
> 
> yields an exception which is an instance of BError.  This instance
> would have as its "context" attribute an instance of AError.
[...]

I like the idea, but I'm not sure about the consequences, and I'm not
sure how it can be defined rigorously. Would it only happen when
something *in* an except clause raises an exception? Which piece of
code would be responsible for doing this?

Try to come up with a precise specification and we'll talk.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)