[Python-3000] __nonzero__ vs. __bool__

[Georg Brandl]

Terry Reedy schrieb:
> "Brett Cannon" <brett at python.org> wrote in message 
> news:bbaeab100611211232r53de3c33p915bee7b49dbdf9a at mail.gmail.com...
> 
> Why can't the fallback usage just pass the return value from __len__ to 
> bool() (forget the C function name) and return that result?  It's just like 
> doing::
> 
>   def bool(obj):
>       try:
>           return obj.__bool__()
>       except AttributeError:
>           return bool(len(obj))
> ------------
> 
> If an object without __bool__ returned itself as its length, this would be 
> an infinite loop, at least in this Python version.  Do we worry about 
> something so crazy?

The length would have to be an integer, and this would have to be checked.

Georg