We discussed polymorphic datatypes, such as SML's built in lists as
well as a user-defined polymorphic tree type.
We wrote several
polymorphic functions, including inord : 'a tree -> 'a
list and polymorphic insertion sort, isort : ('a * 'a -> order) * 'a list -> 'a list.
We discussed how SML infers types of values, including functions.