question about class methods

[Marc 'BlackJack' Rintsch]

In <et9o1i$qfi$1 at ruby.cit.cornell.edu>, Darren Dale wrote:

> I've run across some code in a class method that I don't understand:
> 
>     def example(self, val=0)
>         if val and not self:
>             if self._exp < 0 and self._exp >= -6:
> 
> I am unfamiliar with some concepts here:
> 
> 1) Under what circumstances would "if not self" be True?

If an object is "true" is determined either by a `__nonzero__()` method
that returns `True` or `False` or a `__len__()` method where anything
except 0 means "true".

> 2) If "not self" is True, how can self have attributes?

Attributes are independent from the "truth" value of an object.

Ciao,
	Marc 'BlackJack' Rintsch