[Python-3000] Implementations: A syntax for extending method dispatching beyond type/class inheritance (original) (raw)

Dave Anderson python3000 at davious.org
Thu Dec 7 17:22:47 CET 2006

on 12/7/2006 10:57 AM Hasan Diwan wrote:

On 07/12/06, Dave Anderson <python3000 at davious.org> wrote:

I feel on a different page from you. My best guess it is that def typeOfSuper(self): pass(subclass) is ceding its implementation to its subclasses, kind of like what an abstract class or interface would do but I feel my guess is wrong. Please clarify. No, that is spot-on.

The Implementations syntax sketch has no need for abstract classes, since concrete classes serve as the interfaces. Still, in the syntax, one could simply define a class with a bunch of empty methods, and it would be usable as an abstract class.

The former is an example of someone writing a function whose first parameter is expected to be any object that is derived from MutableContainer (including dict), or is derived from a class that implements MutableContainer (including those implementing dict), or is derived from a class that specifically implements MutableContainer.add using a declaration like:

class CanAdd: implements MutableContainer.add def add(self, key, value): I find you're making the whole "implements" procedure, a little too complex.

Ouch. Touché. :(

Simple things simple. Complex things possible.

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