[Zope3-dev] adaptation based on class rather than interface

[Chris Withers]

Hi All,

I find myself often having to define pure marker interfaces for each 
class that I define, purely so I can register adapters for objects of 
that class.

How do people feel about:

- being able to register an adapter as follows:

<adapter
     for=".myclasses.MyClass"
     provides=".interfaces.ISomething"
     factory=".adapters.MyAdapter"
     />

   ..in addition to the normal registration for interfaces.

- be able to adapt objects based on their class if no interfaces match:

class MyClass: pass

obj = MyClass()

ISomething(obj)

I'm expecting people to say "NO!" very loudly, but I'm interested in the 
real reasons for why this is bad.

Having to define interfaces purely so an adapter can be registered seems 
tortological to me...

Chris

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