[Zope3-dev] Chapter 1 Step 6 now available

[Steve Alexander]

Tres Seaver wrote:
 >
> My problem with Decorator is that it is the name of a recognized
> GoF design pattern;  the Decorator pattern is somewhat like
> adapter, in that the decorating object wraps the decorated,
> but distinct in that the "depended on" and "provided" interfaces
> are the same.
> 
> Maybe I misread Steve's description, and the GoF pattern actually
> fits.

Can you explain why you think my use doesn't fit?

I think it fits.

Take for example

   Decorator.decorate(contactinfo, postalinfo)

...where contactinfo is an object implementing IContactInfo and 
postalinfo is an object implementing IPostalInfo.

Let's call the resultant object decoratedobject.

If you ask for the interfaces that decoratedobject implements, it will 
return exactly the same as contactinfo would.

If you ask for any other attribute of decoratedobject, it will return 
exactly the same as contactinfo would, except where you ask for a method 
of IPostalInfo, where the method of postalinfo will be returned.

Thus, decoratedobject is just like contactinfo, but with methods of 
IPostalInfo bolted on.

Sounds like the Decorator pattern from "Design Patterns: elements of 
reusable object-oriented software" to me.

--
Steve Alexander