[Zope3-dev] Re: Proposal: Improving on __implements__

[Steve Alexander]

Yuppie wrote:
> Steve Alexander wrote:
> 
>> class ServiceSubscriberEventChannel(SubscriptionTracker, EventChannel):
>>     """An event channel that wants to subscribe to the nearest
>>     event service when bound, and unsubscribe when unbound.
>>     """
>>
>>     __implements__ = (
>>         EventChannel.__implements__,
>>         SubscriptionTracker.__implements__,
>>         IBindingAware
>>         )
> 
> 
> Writing code like this (in Zope2) I always had the impression there is 
> something wrong with the syntax:
> 
> Normally I use a superclass because I want to use its interface 
> implementation. Why do I have to add explicitly the inherited interfaces 
> to the declaration?

Because explicit is better than implicit.


> I'd prefer a syntax like this:
> 
> 
> from zope.interface import addImplements
> 
> class ServiceSubscriberEventChannel(SubscriptionTracker, EventChannel):
>     """An event channel that wants to subscribe to the nearest
>     event service when bound, and unsubscribe when unbound.
>     """
> 
>     addImplements(IBindingAware)

That's an interesting idea. Thanks.


A note to anyone interested in this thread: In a few days, I'll collate 
the replies and comments in the wiki, and post a summary of the points 
raised.

--
Steve Alexander