Exceptions as New Style Classes

Carl Banks imbosol at aerojockey.com
Thu Jul 31 09:54:59 CEST 2003

Steven Taschuk wrote:
> Quoth Carl Banks:
>> Steven Taschuk wrote:
>> > At the moment the dominant idea for solving these problems is to
>> > make inheritance from Exception mandatory for exception types; see
>  [...]
>> Why not give exceptions their own metaclass?  So if type(x) is
>> ExceptionMetaclass, it's a class.  If type(type(x)) is
>> ExceptionMetaclass, it's an instance.  Otherwise, it's illegal to
>> raise it.
> That seems workable.  (I'd prefer, though, to test
>    isinstance(type(x), ExceptionMetaclass)
> and likewise for the second case.)
> I'm not sure what it gains us, though, over the idea of mandatory
> inheritance from Exception.  Am I missing something?

Probably not much, unless you think you want to raise exceptions that
aren't subclasses of Exception.


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