[Python-Dev] Breaking calls to object.__init__/__new__
rhamph at gmail.com
Thu Mar 22 22:06:03 CET 2007
On 3/22/07, Thomas Wouters <thomas at python.org> wrote:
> On 3/22/07, Adam Olsen <rhamph at gmail.com> wrote:
> > In general. Too many things could fail without errors, so it wasn't
> > obvious how to use it correctly. None of the articles I've read
> > helped either.
> I've been thinking about writing an article that explains how to use
> super(), so let's start here :) This is a long post that I'll probably
> eventually copy-paste-and-edit into an article of some sort, when I get the
> time. Please do comment, except with 'MI is insane' -- I already know that.
> Nevertheless, I think MI has its uses.
I'm going to be blunt, and I apologize if I offend. In short, your
article is no better than any of the others.
What you've done is list off various ways why multiple inheritance and
super() can fail, and then provide a toolbox from which a programmer
can cobble together a solution to fit their exact needs. It's not
pythonic. What we need is a *single* style that can be applied
consistently to 90+% of problems while still requiring minimal effort
to read later.
Using keyword arguments and consuming them is the best I've seen so
far. Sure it's a little verbose, but the verbosity is repetitive and
easy to tune out. It also requires the classes to cooperate. News
flash: Python isn't C++ or Java. Python uses a shared __dict__ rather
than private namespaces in each class. Python *always* requires the
classes to cooperate.
If you want to combine uncooperative classes you need to use
delegation. I'm sure somebody could whip up a metaclass to automate
it, especially with the new metaclass syntax, not to mention ABCs to
say "I'm string-ish" when you're delegating str.
Adam Olsen, aka Rhamphoryncus
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