3 ms·
It depends. Bare minimum, in scala you have to do: sealed trait Either[A, B] final case class Left[A, B](a: A) extends Either[A, B] final case class Righ
by jbgi 9y ago
It depends. Bare minimum, in scala you have to do:
sealed trait Either[A, B]
final case class Left[A, B](a: A) extends Either[A, B]
final case class Right[A, B](b: B) extends Either[A, B]
and it is still not a real sum type due to exposing subtyping (cf. https://github.com/quasar-analytics/quasar/wiki/Faking-Sum-Types https://github.com/quasar-analytics/quasar/wiki/Faking-Sum-T...)
with derive4j:
@Data
interface Either<A, B> {
<X> X match(Function<A, X> left, Function<B, X> right);
}
or, at your preference:
@Data
interface Either<A, B> {
interface Cases<X> {
X left(A leftValue);
X right(B rightValue);
}
<X> X match(Cases<X> cases);
}
So it is actually not much boilerplate.
The real drawback of (any) java implementation is lack of TCO.