Closure idioms without closures (ML version)

	datatype 'a mylist = Cons of 'a * ('a mylist) | Empty
	fun map f xs =
	case xs of
	Empty => Empty
	| Cons(x,xs) => Cons(f x, map f xs)
	fun filter f xs =
	case xs of
	Empty => Empty
	| Cons(x,xs) => if f x then Cons(x.filter f xs) else filter f xs
	fun lenght xs =
	case xs of
	Empty => 0
	| Cons(_,xs) => 1 + length xs
	(* a valid way to double all numbers in the list
	using partial application *)
	val doubleAll = map (fn x => x * 2)
	(* a way to count N's in a list using partial application *)
	val countNs (xs, n:int) = length (filter (fn x => x=n) xs)

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