1. defgeneric now dispatches on a condition rather than on a specific type. It's a little more verbose but more flexible. I'd already done this in wart almost 3 years ago (http://arclanguage.org/item?id=13790), just been too lazy to update anarki.
2. I've gotten rid of defgeneric; any def can now be generic. This is nice because I don't have to do the whole dance of bootstrap def then unset then defgeneric then defmethods. There's no more code that will get silently overridden.
3. I've merged defmethod and extend into a single name since they now do essentially the same thing. For the new name I'm trying out defextend, but I'm not attached to it.
4. I deleted a couple of libraries that had suffered bitrot or were obsoleted by newer/simpler ideas. They haven't been touched for several years, but feel free to bring them back.
5. As outlined above I've deleted ontree. Use each or walk instead.
6. I've deleted treewise and replaced its calls with reduce.
7. I've deleted tree-subst and replaced its calls with subst, which in turn relies on extensions to map.
