adamc@841: datatype t = datatype Basis.option
adamc@841: 
adamc@846: val eq : a ::: Type -> eq a -> eq (t a)
adamc@846: 
adamc@944: val isNone : a ::: Type -> t a -> bool
adamc@841: val isSome : a ::: Type -> t a -> bool
adamc@844: 
adamc@844: val mp : a ::: Type -> b ::: Type -> (a -> b) -> t a -> t b
adamc@846: val bind : a ::: Type -> b ::: Type -> (a -> option b) -> t a -> t b