[Haskell-beginners] Fwd: Functional Dependencies

[Stephen Tetley]

Hi Dan

I'm not convinced double flattening has a regular type that can be
translated into a type class.

My suspicion is that double flattenable things are nested types not
regular types, though to convince myself I'd have to work it out on
paper which might take some time.

I'd be tempted to avoid a type class for the moment and craft some
non-overloaded double flattening functions and check how regular their
types are.

Regards

Stephen