[Python-Dev] PEP 3144 review.

[Steven D'Aprano]

On Sun, 27 Sep 2009 03:44:45 am Martin v. Löwis wrote:
> >  - Masks are also 32- (128-) bit integers, which happen to have the
> >    property that their leftmost N bits are all zero and the rest
> > are all one.
>
> As a side note, I would be in favor of dropping the concept of a mask
> from the library, and only support a prefix length.

-1

> IPv6 doesn't support masks at all, and even for IPv4, I think there
> are conventions (if not RFCs) against using them in a way that does
> not correspond to a prefix length.

Then the module should only support netmasks of the form 
(say) '255.255.255.224' (equivalent to "/27"), and reject those 
like "255.3.255.255". It currently accepts them.

Many applications still display netmasks in dot-quad form, and I would 
be terribly annoyed if I had to count the bits myself before passing it 
to IPv4Address.



-- 
Steven D'Aprano