[Python-3000] Pre-peps on raise and except changes

[Brett Cannon]

On 1/23/07, Collin Winter <collinw at gmail.com> wrote:
> On 1/23/07, Brett Cannon <brett at python.org> wrote:
> > On 1/23/07, Collin Winter <collinw at gmail.com> wrote:
> > >This form has two sub-variants: ``E`` may be either an
> > >    instance of ``BaseException`` [#pep352]_ or a subclass of
> > >    ``BaseException``. If ``E`` is a subclass, it will be called with
> > >    no arguments to obtain an exception instance.
> > >
> > >    To raise anything else is an error.
> > > """
> >
> > I don't think that calling them a variant is right.  You can only
> > raise subclasses of BaseException (which implicitly implies
> > BaseException itself).  If you want to mention BaseException itself
> > that's fine, but there is no variant here; there is a single rule.
>
> You can raise both subclasses of BaseException and instances of
> subclasses of BaseException. Are you intended to make the latter
> illegal?
>

No, of course not.  As long as BaseException is in the inheritance
tree you are fine.

I just realized I misread your paragraph and took E to represent an
exception class, not a nebulous object that could be an exception
class or instance.

-Brett