I am writing (another) modular interpreter in Haskell (Hugs98 actually). I keep having problems with multiparameter type classes. Is there any sort of user's manual for this yet non-standard construct? I understand the idea, and it is all fine when it works, but there are many restrictions that I do not understand. I am not sure I am ready to delve into all implementation details to undestand why e.g. some instance declarations are allowed and some not. Viktor
