[Zope] Attribute lookup

[J. Cameron Cooper]

> I have a class A, and another class B which is a wrapper for it (a 
> Product, inherited from SimpleItem.SimpleItem). I want B to delegate 
> most attributes to A:
>
> class A:
>         def __init__(self, title, ...):
>                 self.title = title
>                 ....
>
> class B(SimpleItem.SimpleItem):
>         def __init__(self, id, title):
>                 self.id = id
>                 self.innerA = A(title)
>
>         def __getattr__(self, name):
>                 return getattr(self.__dict__['innerA'], name)
>
> This works fine for most attributes *but* title. SimpleItem.Item has a 
> class attribute 'title' and, altough B instances have no 'title' 
> attribute at all, they inherit an empty class attribute 'title' from 
> Item, and never goes thru __getattr__.
> How could I arrange things so 'title' comes from inner A instance, and 
> *not* from Item base class?

A curious arrangement. Take a look at this little experiment on a Python 
console::

 >>> class A:
...   title = 'dog'
...
 >>> class I:
...   title = 'cat'
...
 >>> class B(I):
...   innerA = A()
...   title = A.title
...
 >>> B.title
'dog'

Looks like that works as you want.

          --jcc

-- 
"My point and period will be throughly wrought,
Or well or ill, as this day's battle's fought."