[Python-Dev] PEP 340 -- concept clarification

[Phillip J. Eby]

At 03:33 PM 5/3/05 -0700, Guido van Rossum wrote:
>[Phillip]
> > That reminds me of something; in PEP 333 I proposed use of a 'close()'
> > attribute in anticipation of PEP 325, so that web applications implemented
> > as generators could take advantage of resource cleanup.  Is there any
> > chance that as part of PEP 340, 'close()' could translate to the same as
> > '__exit__(StopIteration)'?  If not, modifying PEP 333 to support '__exit__'
> > is going to be a bit of a pain, especially since there's code in the field
> > now with that assumption.
>
>Maybe if you drop support for the "separate protocol" alternative... :-)

I don't understand you.  Are you suggesting a horse trade, or...?


>I had never heard of that PEP. How much code is there in the field?

Maybe a dozen or so web applications and frameworks (including Zope, 
Quixote, PyBlosxom) and maybe a half dozen servers (incl. Twisted and 
mod_python).  A lot of the servers are based on my wsgiref library, though, 
so it probably wouldn't be too horrible a job to make everybody add 
support; I might even be able to fudge wsgiref so that wsgiref-based 
servers don't even see an issue.

Modifying the spec is potentially more controversial, however; it'll have 
to go past the Web-SIG, and I assume the first thing that'll be asked is, 
"Why aren't generators getting a close() method then?", so I figured I 
should ask that question first.

I'd completely forgotten about this being an issue until Raymond mentioned 
g.close(); I'd previously gotten the impression that PEP 325 was expected 
to be approved, otherwise I wouldn't have written support for it into PEP 333.


>Written by whom?

I used to know who all had written implementations, but there are now too 
many to keep track of.