Re: Conditionally render viewlet

>> The viewlet still rendered even though theres no index_left.
>> Then I checked the documentation here
>> http://pypi.python.org/pypi/zope.viewlet, specifically the
>> 'ConditionalViewletManager' section where it states that Viewlets have
>> an 'available' attribute (not a method), so I tried setting available
>> = False,  but still the viewlet rendered.

You're right, Viewlet have no available method, I've been mistaken.
What we usually do is this:

In the viewlet manager we override the filters method :

class MyViewletManager(...):
   ...
   def filter(self):
      viewlets = super(MyViewletManager, self).filter()
      return [v for v in viewlets if v.available()]

Then define an available method on all viewlets of this ViewletManager.

BTW, be carefull with hasattr(self.context, 'index_left'), it checks
with acquisition.

Antonin