adamc@191: datatype option a = None | Some of a
adamc@191:
adamc@191: val none : option int = None
adamc@191: val some_1 : option int = Some 1
adamc@191:
adamc@191: val f = fn t ::: Type => fn x : option t =>
adamc@191: case x of None => None | Some x => Some (Some x)
adamc@191:
adamc@191: val none_again = f none
adamc@191: val some_1_again = f some_1
adamc@193:
adamc@193: val show = fn t ::: Type => fn x : option t => case x of None => "None" | Some _ => "Some"
adamc@193:
adamc@193: val page = fn x =>
adamc@193: {cdata (show x)}
adamc@193:
adamc@193:
adamc@193: val main : unit -> page = fn () =>
adamc@193: None
adamc@193: Some 1
adamc@193: