Intercept operator lookup on metaclass

Question

I have a class that need to make some magic with every operator, like __add__, __sub__ and so on.

Instead of creating each function in the

Answer 1

The issue at hand is that Python looks up __xxx__ methods on the object's class, not on the object itself -- and if it is not found, it does not fall back to __getattr__ nor __getattribute__.

The only way to intercept such calls is to have a method already there. It can be a stub function, as in Niklas Baumstark's answer, or it can be the full-fledged replacement function; either way, however, there must be something already there or you will not be able to intercept such calls.

If you are reading closely, you will have noticed that your requirement for having the final method be bound to the instance is not a possible solution -- you can do it, but Python will never call it as Python is looking at the class of the instance, not the instance, for __xxx__ methods. Niklas Baumstark's solution of making a unique temp class for each instance is as close as you can get to that requirement.