it seems like we cannot cast the class of object to its subclass if that
subclass has had new instance variables added to it:
But I (think) I need it - I'm transforming a DOM tree from XMLHTMLParser's
XMLElement s to a subclass of Iliad's ILHTMLBuilderElement s, and for
single occurences I would like to use the more specific subclasses, like
ILCheckboxElement. I can make the cast manually, I know when it is safe to
What else could I do, apart from removing the element from its tree,
creating a new (subclass) instance and then putting this element in place
of the old one? Some #perform or `super` magic..?
thanks for any pointers!