[Python-Dev] Py3K: indirect coupling between raise and exception handler

[Tim Peters]

[Skip Montanaro, with an expression that may raise TypeError for any of
 several distinct reasons, and wants to figure out which one after the fact]

The existing exception machinery is sufficiently powerful for building a
solution, so nothing new is needed in the language.  What you really need
here is an exhaustive list of all exceptions the language can raise, and
when, and why, and a formally supported "detail" field (whether numeric id
or string or whatever) that you can rely on to tell them apart at runtime.

There are at least a thousand cases that need to be so documented and
formalized.  That's why not a one of them is now <0.9 wink>.

If P3K is a rewrite from scratch, a rational scheme could be built in from
the start.  Else it would seem to require a volunteer with even less of a
life than us <wink>.