Home Original page

[Python-Dev] PEP 3144 review.

"Martin v. Löwis" martin at v.loewis.de
Mon Sep 28 05:57:04 CEST 2009 
>> Finally, to Stephen's point about seeing the other side of the
>> argument, I wrote this offlist a week ago:
>>
>>   I *understand* what you're saying, I *understand* that
>> 192.168.1.1/24 isn't a network, 
> 
> But you still want to treat it as one.
> 
> Could you explain what benefit there is for allowing the user to create 
> network objects that don't represent networks? Is there a use-case 
> where these networks-that-aren't-networks are something other than a 
> typo? Under what circumstances would I want to specify a network as 
> 192.168.1.1/24 instead of 192.168.1.0/24?
> 

It's fairly obvious to me why the library should support 192.168.1.1/24
as an input, and return a network.

End-users are likely going to enter such things (e.g. 82.94.164.162/29),
as they will know one IP address in the network (namely, of one machine
that they are looking at), and they will know the prefix length (more
often, how large the network is - 8 or 16 or 32). So very clearly,
end users should not be required to make the computation in their heads.

So Python code has to make the computation, and it seems most natural
that the IP library is the piece of code that is able to compute a
network out of that input.

Does that answer your question?

Regards,
Martin
More information about the Python-Dev mailing list