[Python-3000] self-contained exceptions

Thu Jan 4 20:33:18 CET 2007

[Guido]
> The use case I am guessing from your example (passing a
> traceback as a single string across an RPC boundary) isn't all that
> common and you ought to have only one place in your RPC package where
> you need to call it.

*this* use-case isn't that useful, true. but many times, frameworks need
to store the exception details "for later", for example, unit-testing.
you want to run the entire test, and print a report later.
if exceptions formatted themselves (via repr or something like it),
all of these use cases would have been trivial, and there would be
no need for the traceback module at all or excepthook.
(we would still need excepthook, but only in order to redirect printouts
to other file objects other than stderr.)
imho it's more pythonic to have the exception object be self-contained,
rather than having its state scattered around different modules
(sys, exceptions, and traceback). besides, today exceptions are
made of three separate "components" (type, value and tb), which
can all be unified once string exceptions are removed and exceptions
become new style classes.
if pep 344 is going to solve that, of course i'm +1 and there's no need
for a "competing" version... but the pep has been dormant for so long
that i thought it was neglected.
is this pep going to make it for py3k? any pronouncement on the subject?
-tomer