Chris Withers wrote:
 >>> provideAdapter(to_date,(str,int),DateTime)

This registers a multi adapter for (a_string, an_integer), like views are multi-adapters for (context, request). You want to say:

  >>> provideAdapter(to_date, (str,), DateTime)
  >>> provideAdapter(to_date, (int,), DateTime)

Ahhhh... okay, I had to guess from this:

Don't guess, just look at the docs that are there.

 >>> help(provideAdapter)
Help on function provideAdapter in module zope.component:

provideAdapter(factory, adapts=None, provides=None, name='')

 >>> provideAdapter(str,int,str)
TypeError: iteration over non-sequence

I guessed the wrong use of the sequence :-(

Shame provideAdapter doesn't have a docstring ;-)

It does -- in the interfaces. Like it or not, Zope 3's API *is* well documented, if you look in the right places: the interfaces. That's what they're there for.

Okay, so now I can do what I want:

 >>> getAdapter('2006/11/16',DateTime)


 >>> getAdapter('moo',DateTime)
('moo', <class DateTime.DateTime.DateTime at 0x00E73600>, u'')

I'm guessing this is 'cos my adapter is returning None

Adapter factories can return None to indicate that adaption has failed.

and that's a "special value" meaning "couldn't adapt", right?


How would I _really_ return None from an adapter?

You don't. You call the adaption with a default value (e.g. None) to cover for the "coudln't adapt" case:

  >>> getAdapter('moo', DateTime, None)

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