[Zope3-dev] Re: wildcard adapter

[Philipp von Weitershausen]

On 18 Jan 2007, at 09:53 , Chris Withers wrote:
> Philipp von Weitershausen wrote:
>>> If it is, then which of the following should I use to register a  
>>> generic adapter for any single object to an interface:
>>>
>>> provideAdapter(...,adapts=(None,),...)
>> This one.
>
> Given that you can register adapters for any class, whether or not  
> it implements any interface, this doesn't work as it should:
>
> >>> from zope.component import provideAdapter
> >>> def adapter(*args): pass
> ...

This is your problem. The 'adapter' function is a factory so it's  
supposed to actually return the value of the adaption. If ITest(1)  
returns None, then the component architecture thinks adaption has  
failed. This is a well-known and intended behaviour.

> >>> from zope.interface import Interface
> >>> class ITest(Interface): pass
> ...
> >>> provideAdapter(adapter,adapts=(None,),provides=ITest)
>
> >>> ITest(1)
> Traceback (most recent call last):
> ...
> TypeError: ('Could not adapt', 1, <InterfaceClass __main__.ITest>)
>
> >>> class test: pass
> ...
> >>> ITest(test())
> ...
> TypeError: ('Could not adapt', <__main__.test instance at ...>,  
> <InterfaceClass __main__.ITest>)
>
>> I have no idea what a "generic" adapter is, but the zope.component  
>> API docs (== interfaces) are certainly complete in this sense.  
>> There are also doctests.
>
> Where can I find the docs and interfaces you mention above? I  
> looked through both zope.interface and zope.component and obviously  
> missed them :-(