Re: [Zope] Attribute lookup

4 Nov 2003


      
...
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."

Re: [Zope] Attribute lookup

J. Cameron Cooper