Re: Overloading operators

[Lie Ryan]

On Wed, 15 Oct 2008 14:34:14 +0200, Mr.SpOOn wrote:

Hi,
in a project I'm overloading a lot of comparison and arithmetic
operators to make them working with more complex classes that I defined.
What is the best way to do this? Shall I use a lot of "if...elif"
statements inside the overloaded operator? Or is there a more pythonic
and dynamic way?

Something that is more pythonic is something that doesn't use
multimethods. It's just an elaborated way to do type checking. In python,
you usually avoid type checking and if-elif-block-with-isinstance in
favor of Duck Typing and EAFP (Easier to Ask Forgiveness than Permission,
i.e. try-block).

Sometimes I need a different behavior of the operator depending on the
argument. For example, if I compare a object with an int, I get a
result, but if I compare the same object with a string, or another
object, I get another result.

*smells a bad class design* If that is the case, I'd recommend on
splitting that behavior into two or more functions/operators (or possibly
splitting the class). It's hard to reason the behavior of a class if the
class is that complex (Simple is better than complex; Complex is better
than complicated. The Zen of Python this:2-3).