On Wed, Sep 30, 2009 at 4:33 AM, Mark Dickinson <dicki...@gmail.com> wrote: > On Wed, Sep 30, 2009 at 12:06 PM, Nick Coghlan <ncogh...@gmail.com> wrote: >> Mark Dickinson wrote: >>> Okay, so maybe this is an abuse of IPv4Network. But I'd (mis?)understood >>> that the retention of the .ip attribute was precisely a convenience to allow >>> this sort of use. If not, then what's it for? I've read the PEP and almost >>> all of this thread, but I can't help feeling I'm still missing something. >>> If >>> someone could point out the obvious to me I'd be grateful. >> >> You're not missing anything that I'm aware of - unlike the use case for >> accepting a denormalised network definition in the IPNetwork constructor >> (which has been made quite clear in the list discussion, even if it is >> still a bit vague in the PEP), the use case for *retaining* the host >> information on the network object hasn't been well articulated at all. >> >> The closest anyone has come to describing a use case is an indirect >> comment via Guido that leaving out the attribute would involve real code >> having to find somewhere else to stash the original address details >> (e.g. by passing around an IPAddres/IPNetwork tuple rather than just an >> IPNetwork object). > > Ah, thanks---I'd missed that bit. So the .ip attribute is mainly for > backwards compatibility with existing uses/users of ipaddr. I guess > that makes sense, then. In particular, if it's suggested that new code > shouldn't make use of the .ip attribute, then the list/dict membership > problems described above can't arise.
I don't know -- this is (from what Peter told me) a common use case so he (and presumably others) would from time to time have to write extra code to keep track of that IP address in a new app. Since this is just one extra attribute on an IPNetwork object I don't think that adding extra classes which only differ from the IPvXNetwork classes in having this one extra attribute is worthy. -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
