[Baypiggies] Frequently Argued Objections

[Shannon -jj Behrens]

On Tue, Jun 24, 2008 at 10:28 AM, Alex Martelli <aleax at google.com> wrote:
> On Tue, Jun 24, 2008 at 5:03 AM, Shannon -jj Behrens <jjinux at gmail.com> wrote:
>> Your post did bring up one thing I do like about Ruby.  It has a more
>> defined notion of class scope at class definition time.  If Python had
>> that, I could do something like:
>>
>> class B(A):
>>    ...
>>    if hasattr(B, 'foo'):
>>        ...
>>
>> That's not possible now, because B doesn't exist until the class is
>> finished being defined.  There are workarounds.  It's not a big deal.
>> I'm just saying ;)
>
> Why do you consider "a workaround" to code for such weird needs:
>
>>>> class B(object):
> ...   foo = 23
> ...   if 'foo' in locals(): print 'foo is', foo
> ...   else: print 'no foo'
> ...
> foo is 23
>
> Seems very direct to me -- the class's direct attributes are kept in
> the class body's locals() while said body executes, and that's the
> dict that's passed to the metaclass's __new__ (and possibly __init__)
> (plus of course each base class may have more attributes). This is a
> perfectly well defined and documented "notion of scope during class
> definition" (even though I've never felt the need to use it within the
> class body, as opposed to using it in some metaclass).  What am I
> missing?

Thanks, Alex, I didn't know about that ;)

-jj

-- 
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