[Python-Dev] Re: [Python-checkins] CVS: python/dist/src/Lib getopt.py,1.7,1.8

[Guido van Rossum]

> From: "Fred L. Drake, Jr." <fdrake@acm.org>
> 
> Guido van Rossum writes:
>  > (The next step would be to outlaw raise with a string argument; I
>  > think I can't make that for 1.6.  But it would be a good idea to scan
>  > the standard library for string exceptions and convert all of them.)
> 
>   I don't know if requiring class-based exceptions will make the
> runtime any simpler, but that seems the only reason to do it.

Do what?  *Require* class exceptions?  You're probably right, and I
think the gain is minimal.

There's another reason to scan the std library though -- not to set a
bad example.  I want to eventually (in 2.0) move to a
class-derived-from-Exception-only scheme.

>   The only reason to remove -X, and possibly the string exception
> fallback code, is to ensure that we *can* subclass Exception and
> friends without having to catch TypeError and do something different.

And that's a very good reason indeed.

Let me repeat my plans for 1.6.

- Remove -X; the standard exceptions are always class-based.

- Change all standard library and other example code to use
class-based exceptions with a standard exception as base class, to set
an example.

- Still allow string exceptions in user code.

- Still allow class exceptions that don't use a standard exception
base class in user code.

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