[Zope3-dev] Ranking adapters (2nd try)

[Steve Alexander]

Phillip J. Eby wrote:
> At 08:26 PM 9/30/03 +0300, Steve Alexander wrote:
> 
>> I was suggesting that if I register locally an adapter to B2 that this 
>> implies registration of that adapter to B1 and B0 also.
> 
> What happens if you *subsequently* register an adapter to B0?  Does it 
> override the adapter declared to B2, where B0 is concerned?

In my naive system, that sounds like a conflict.

<advocate owner="devil">
   If you have the requirement to use different adapters to B0 and
   to B2 at the same time, you have a "Liskov-fragile" system.
</advocate>


> Unfortunately, not only is a ranking semantic needed, but the system 
> must account for the effects of changes to the inputs of that ranking, 
> as well as changes in the available adapters to be ranked.

Only if you decide you need to register B0s and B2s with B0s being more 
important than B2s. I haven't heard a good use-case for that on this 
thread yet.


> Ideally, declaration/registration order should not have any effect on 
> the resulting precedence(s).

I agree.

--
Steve Alexander