Re: [Haskell-beginners] How to nest arbitrary things

On Mon, Dec 21, 2015 at 8:51 PM, Imants Cekusins wrote: data Item a = Truck a [Item] | Box a [Item] | Parcel a [Item] | Can a [Item] A cardinal rule of FP data modelling is to avoid the hazards of junk, a.k.a. make the meaningless unspeakable. Here an Item could be a Can that contains a Parcel that contains a Box that in turn has a Truck inside. What will Item-processing functions do with this Item? Garbage In Garbage Out. -- Kim-Ee