Sum types

[KacperFKorban]

Only concrete types are supported ATM.

closes #21

e.g.

sealed trait MaybeString
case class JustString(value: String) extends MaybeString
case object NoString extends MaybeString

def nameWithPossiblePrefix(name: String, maybePrefix: MaybeString): String =
  maybePrefix match
    case JustString(value) => s"$value $name"
    case NoString => name

guinep.web(nameWithPossiblePrefix)