>It seems kind of harsh that Squeak crashes on a recursive
>#doesNotUnderstand: (when an object (a subclass of nil) does not
>understand #doesNotUnderstand:).

This is a HUGE issue for my students, who are just learning about 
changesets and filing out categories/classes.  They often create 
classes with nil superclasses, which leads to the kinds of crash that 
Stephen describes.

Mark

--------------------------
Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
Associate Professor - Learning Sciences & Technologies.
Collaborative Software Lab - http://coweb.cc.gatech.edu/csl/
(404) 894-5618 : Fax (404) 894-0673 : guzdial at cc.gatech.edu
http://www.cc.gatech.edu/gvu/people/Faculty/Mark.Guzdial.html