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[Python-Dev] conceptual clarity

Eric Smith eric at trueblade.com
Thu Sep 17 14:14:34 CEST 2009 
Antoine Pitrou wrote:
> Le Thu, 17 Sep 2009 14:30:28 +1200, Greg Ewing a écrit :
>> 3) an Address with an attached Network
>>
>> An Address could be constructed in three ways:
>>
>>    Address(ip_number)
>>
>>    Address(ip_number, network = <Network instance>)
>>
>>    Address(ip_number, mask = <mask>)
>>      # constructs and attaches a suitably-masked Network instance
>>
>> We could also have some_network[n] return an Address referring back to
>> the network object it was obtained from.
> 
> It seems you are uselessly conflating two perfectly distinct concepts: 
> Address and Network. You also haven't addresses the issue of comparing 
> together (and hashing) two addresses with the same IP but pointing to a 
> different network. No answer to this issue seems satisfactory and 
> obviously right.
> 
> As it is, -1 from me. Either we only keep two concepts (Address and 
> Network), or if we introduce a third one (AddressWithMask, whatever) for 
> added practicality; but we shouldn't blur the line between the two former 
> canonical concepts under the pretext that a platypus-like Address might 
> be helpful in some particular situations.

I completely agree with this. By keeping the concepts distinct we can 
catch mis-uses earlier. If needed, convenience functions (or classes, or 
whatever) could be layered on top. But the underlying concepts need to 
be clear.

Eric.
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