[Zope3-dev] Re: adapter registration question

[Tres Seaver]

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Chris Withers wrote:
> Tres Seaver wrote:
>> We were discussion a (notional) "value adapter", whose factory would
>> have the contract of returning an object of a specific concrete type,
>> rather than on implementing an interface.
> 
> Right, but the CA supports the use of classes instead of interfaces and 
> that works just fine here...
> 
>> There are reasonable usecases
>> for such adapters, but the CA machinery doesn't permit registering them:
>>  it requires that the 'provided' argument be either an interface or None
>> (although the 'required' args can be concrete types).
> 
> Nah, for both "provides" and "adapts" classes can be used in place of 
> interfaces just fine, and I've got this working just how I want it now :-)

This doctest blows up on my machine when run against the Zope3 trunk:

  >>> from zope.component import getAdapter
  >>> from zope.component import provideAdapter
  >>> from zope.interface import Interface
  >>> from zope.interface import implements
  >>> class IFoo(Interface):
  ...     pass
  >>> class Foo(object):
  ...     implements(IFoo)
  >>> foo = Foo()
  >>> def get_a(x):
  ...     return 'a'
  >>> def get_b(x):
  ...     return 'b'
  >>> provideAdapter(get_a, adapts=(IFoo,), provides=str, name='a')
  >>> provideAdapter(get_b, adapts=(IFoo,), provides=str, name='b')
  >>> getAdapter(object=foo, interface=str, name='a')
  'a'
  >>> getAdapter(object=foo, interface=str, name='b')
  'b'


The first 'provideAdapter' call raises an exeption because 'str' doesn't
have an '__iro__'.  The second *doesn't* raise, because the code which
raised the first exception leaves an artifact in a module global.

Bot lookups fail with 'ComponentLookupError'.


Tres.
- --
===================================================================
Tres Seaver          +1 202-558-7113          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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