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[Python-Dev] PEP 3144 review.

Greg Ewing greg.ewing at canterbury.ac.nz
Thu Sep 17 01:56:25 CEST 2009 
R. David Murray wrote:

> A network is conventionally represented by an IP address in which the
> bits corresponding to the one bits in the netmask are set to zero, plus
> the netmask.

Okay, that's clarified things for me, thanks.

In that case, we shouldn't be talking about a "network address"
at all, but just a "network", and it makes sense to have

1) A class called IPNetwork that contains an IP number
and a mask, with the IP number constrained not to have
any ones where the mask has zeroes, and

2) A class called IPAddress which only contains an
IP number.

It seems that some people would also like to have

3) A class called IPAddressWithMask that contains an
IP number and a mask, with no constraints,

but I'm not enough of an expert to know whether such
a thing would be used often enough to be worth having
a special type for it, as opposed to using an
(IPNetwork, IPAddress) pair, or attaching a 'network'
attribute to an IPAddress, or some other solution
when the need arises.

-- 
Greg
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