def List.head
import Base964def List.head(a, -A: Kind(a), xs: List<a, A>) -> Maybe<a, A>:
965 match xs:
966 case Nil{}:
967 None{}
968 case h <> t:
969 Some{h}
import Base964def List.head(a, -A: Kind(a), xs: List<a, A>) -> Maybe<a, A>:
965 match xs:
966 case Nil{}:
967 None{}
968 case h <> t:
969 Some{h}