[Python-3000] self-contained exceptions

[Greg Falcon]

On 1/10/07, Josiah Carlson <jcarlson at uci.edu> wrote:
> According to the translation rules Colin has previously provided...
>
>     re = get_resource()
>     ...
>     try:
>         something()
>     except RareException as re:
>         ...
>     ...
>     re.use_resource()
>
> is translated into...
>
>     re = get_resource()
>     ...
>     try:
>         try:
>             something()
>         except RareException:
>             re = <current exception>
>             ...
>     finally:
>         re = None
>         del re
>     ...
>     re.use_resource()

That's not what I understand the transformation to be.  I thought the
transformation we were talking about was:

    re = get_resource()
    ...
    try:
        something()
    except RareException, re:
        try:
            ...
        finally:
            re = None
            del re
    ...
    re.use_resource()

Per these rules:
On 1/7/07, Collin Winter <collinw at gmail.com> wrote:
> > On 1/4/07, Phillip J. Eby <pje at telecommunity.com> wrote:
> > >       except ExcType, e:
> > >           try:
> > >               # body
> > >           finally:
> > >               e = None
> > >               del e
> The transformation is as Phillip outlined above, with extra logic to
> handle the case where e is a tuple or list.

Perhaps the example transformation you provided is better, in that at
least you can't make the mistake I'm worried about.  But it seems a
bit gratuitous (and expensive) to delete N variables when there are N
except clauses.

In any event, if I was mistaken about the transformation that occurs,
I apologize and withdraw my SyntaxWarning suggestion.

Greg F