However, seems legit, but maybe there is an existing tool for such kind of tasks.

You could just use `filter`:

filter { it.contactInfo.isRight || it.contactInfo.isBoth }

Hey @rcd27, Looks like you might be able use the

ior

binding for this.

ior(semigroup) {
  listOf(
    contactWithAddres,
    contactWithMail
   ).map { it.contactInfo.bind() }
  }
}

@Lukasz Kalnik the idea of picking

Ior

was that it represent either left, or right, or both. And I still don't know how to model that by hands, Nullability of those two values means that there is a 4th case: both missing, which is not valid for this case.

Ah, that's a very interesting case. So you need a guarantee that at least one of them is present. What about

NonEmptyList

?