Re: [Haskell-beginners] Constructor classes and type classes.

this builds. not sure if the instances are as intended {-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-} module SetClass where data TimeFacts t = Bef (t, t, TimeFacts t) | New class SetClass t where class SetClass t => Time l t where class Time l t => TimeE l t where class Time l t => TimeTO l t where instance SetClass (TimeFacts t) where -- OK instance (SetClass t) => Time (TimeFacts t) t where instance (SetClass t) => TimeE (TimeFacts t) t where instance (SetClass t) => TimeTO (TimeFacts t) t where ​