Implementation of IBuyable or Interface?

[Gabriel Genellina]

En Tue, 29 Jan 2008 15:52:58 -0200, Marcelo de Moraes Serpa  
<celoserpa at gmail.com> escribi�:

> I've got a IBuyable interface. The app can sell both Products and  
> Services
> (Both "Buyables"). I'm not sure if Product and Service should also be
> represented as interfaces (inherited from IBuyable) or if they are  
> actually
> directly implementations of IBuyable.

It's hard to tell just with that description. If you have to distinguish  
between a Product and a Service, specially if you have to do things with  
one that aren't done with the other (so they have a different set of  
methods), I'd say they should be different interfaces.
Of course you may have several classes implementing the same interfaces.

BTW, what do you use to define the interface? zope.inteface? another  
package?

-- 
Gabriel Genellina