[Python-Dev] PEP 3144 review.

[Steven D'Aprano]

On Mon, 28 Sep 2009 02:47:27 am Peter Moody wrote:

> > There was a proposal to have a separate parse_address_and_mask
> > method which would return a (Address, Network) tuple, I still don't
> > know why you don't seem to consider it seriously, rather than
> > trying to make the Network class a kind of all-in-one type
> > conflating different concepts.
>
> The reason (aside from the name) that I'm not going to include this
> in ipaddr is that it would require the user to deal with two objects
> when one would suffice. It's similar to getting two return values 
> from float().
>
>  integer, fraction = float('1.25')
>
> crazy, right?

Not if you want a separate integer and fraction object. There are plenty 
of use-cases for such things, and the math module includes a function, 
modf(), that does precisely that.. 


> 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?



-- 
Steven D'Aprano