datatype list a = Nil | Cons of a * list a val isNil = fn t ::: Type => fn ls : list t => case ls of Nil => True | _ => False val show = fn b => if b then "True" else "False" val rec delist : list string -> xml body [] [] = fn x => case x of Nil => Nil | Cons (h, t) => {cdata h} :: {delist t} val main : unit -> page = fn () => {cdata (show (isNil (Nil : list bool)))}, {cdata (show (isNil (Cons (1, Nil))))}, {cdata (show (isNil (Cons ("A", Cons ("B", Nil)))))}

{delist (Cons ("X", Cons ("Y", Cons ("Z", Nil))))}