[Twisted-Python] Interfaces and adapters

[Bob Ippolito]

On Aug 25, 2005, at 11:30 PM, Andrew Bennetts wrote:

> On Fri, Aug 26, 2005 at 10:17:07AM +0400, en.karpachov at ospaz.ru wrote:
>
>> Let's say we defined an interface and an adapter:
>>
>> class IFoo(zope.interfaces.Interface):
>>     pass
>>
>> twisted.python.components.registerAdapter(Foo, Bar, IFoo)
>>
>> As it is for now, the registerAdapter accepts any Foo, without  
>> regarding
>> what it implements.
>>
>
> It has to accept pretty much anything -- adapters can be e.g.  
> functions as
> well as classes.
>
>
>> Could somebody give any rationale why this condition shouldn't  
>> always hold:
>>
>> foo = IFoo(bar)
>> assert IFoo.providedBy(foo)
>>
>> Seems it is not unreasonable to expect this behaviour, because it is
>> exactly what interfaces are all about, or am I wrong?
>>
>
> That's a pretty reasonable expectation.  I think emitting a warning  
> if this
> doesn't hold would be a sane thing to do, and it wouldn't break any  
> code.

It would certainly slow it down, though.  I think this is a  
"consenting adults" kind of scenario.  If someone registers an  
adapter, they probably didn't do it by accident!

-bob