I need to re-write the RuleCompiler!

Damn! I really thought I would be able to debug my way into a decent RuleCompiler; but I keep getting lost. There are a couple of cases that it can't handle. At all. And another couple of cases which it *can* handle, if you type the Conditions in the "correct" order ;-)

Unfortunately the constructRete method has just grown and grown (and I haven't written doctests for it) so now, I've come to the point where it's easier to re-write than to carry on. Implementation of Not and Exists will have to wait...