On 3/2/07, Greg Ewing <[EMAIL PROTECTED]> wrote: > Guido van Rossum wrote: > > > I'm afraid we're back at square zero; perhaps we should keep the > > existing (type, value, traceback) API > > Whatever happens, we should be able to get that down > to at most two things: (exception, context) where > exception is either a class or an instance, and > context includes the traceback and anything else > that varies from one raising to another. > > > rather than going for radical > > (and unproven) innovation like "except E as v with tb: <block>". > > The "with something" clause isn't mutually exclusive > with that -- rather it goes hand-in-hand as a nicer > way of getting hold of the context than calling > sys.exc_info(). I'd consider it an optional extra. > > > "except E as v with tb in context for cause" anyone? :-) > > I was thinking more of > > except E as v with context: > > and context would have attributes such as traceback, > cause, etc. > > (Although calling it a "context" could be seriously > confusing, considering we also have a "with" statement > having something called a context that's completely > different.) > > > The one thing that makes me not want to give up yet is that having the > > traceback, context, cause etc. as attributes of the exception object > > would seem to make the API for handling exceptions that much cleaner, > > If we can get it down to a 2-tuple, with no fudging > around to allow for sometimes having the args separate > from the type but not always, that should simplify it > considerably. > > One thing I would like to get out of it if possible > is the chance to raise and catch an exception class > without instantiating it at all under favourable > circumstances. That should be possible if we allow > the first item of the tuple to be either a class or > instance, and not bother instantiating if it's a > class and gets caught with > > except E: > > or > > except E with context:
But what's the advantage of not instantiating the exception if we instantiate the context instead? I really think that it would be nicer if the exception object *was* the context. We'd still not have to instantiate if it was just "except E:" but that can be handled behind the scenes. -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
