On Jul 11, 6:38 pm, Robert Bossy > I don't get it. Why use a metaclass? Wouldn't the following be the same, > but easier to grasp: > > class Frozen(object): > def __setattr__(self, name, value): > if not hasattr(self, name): > raise AttributeError, "cannot add attributes to %s" % self > object.__setattr__(self, name, value)
This is easier, but it does not stop the user from adding class level attributes: this is the job of the metaclass. If you don't care about class level attributes (including methods, properties, etc) and you are content with restricting only the instance attributes your recipe is fine, yes. -- http://mail.python.org/mailman/listinfo/python-list
