[Python-3000] __nonzero__ vs. __bool__

[Terry Reedy]

"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?

tjr