Any way of adding methods/accessors to built-in classes?

[bearophileHUGS at lycos.com]

Kenneth McDonald:
> not being able to do things like '[1,2,3]'.length
> drives me a little nuts.

This is interesting, why?
(In a computer language too much purity is often bad. And isn't
[1,2,3].len better?)

I think you can't add methods to Python builtin classes, I think you
can do it with Ruby.

Bye,
bearophile