Ben Finney wrote: > How can a (user-defined) class ensure that its instances are > immutable, like an int or a tuple, without inheriting from those > types? > > What caveats should be observed in making immutable instances?
In short, you can't. I usually try harder to derive from tuple to achieve this (defining a few read-only properties to access item through attributes). Using __slots__ is then required to avoid people adding attributes to the instance. In fact, I don't know the rationale. I would think it would be a great addition to be able to say __immutable__ = True or something like that. Or at least, I'd be grateful if someone explained me why this can't or shouldn't be done. -- Giovanni Bajo -- http://mail.python.org/mailman/listinfo/python-list
