I want to thank everybody for the kind explanations of kind errors. I think I now understand them (figured it out through a LOT of trial and error). The problem (as Carl and others noted) was I was testing various ways of doing things using synonyms rather than data types and didn't know that you can't do that! Based on my recent experience as a new coder, here are some words of advice for future beginners: * Beware the monomorphism restriction! * Avoid type synonyms in instance declarations! * use newtype whenever possible (also see quickcheck docs) * you can't use existential types except through class methods! * you must wrap existential types if you want to use them in record-style data declarations (No, I have no idea why this is, but it appears to be true nonetheless) The problem with this sort of list is that it is probably only useful after you have already made these mistakes. Oh well. -Alex- _________________________________________________________________ S. Alexander Jacobson mailto:me@alexjacobson.com tel:917-770-6565 http://alexjacobson.com