What's the best way to "flatMap" two or more validated nels ?

# arrow

[sam]

What's the best way to "flatMap" two or more validated nels ?

[sam]

sequenceValidated

?

[sam]

I kinda wanna do something like this

val p1: (T) -> ValidatedNel<E, A>
val p2: (T) -> ValidatedNel<E, B>
p1(t).flatMap { a -> p2(t).map { b-> Pair(a, b) } }

[Wesley Hartford]

Is zip what you're looking for?

p1(t).zip(p2(t)) { a, b -> Pair(a, b) }

I think that works, not sure though.

[sam]

Yep that's it, thanks @Wesley Hartford

[Wesley Hartford]

Awesome, glad to help

[raulraja]

In addition to zip as @Wesley Hartford pointed out one can bind Validated values inside either blocks and use them as if they were of type Either .

either<E> {
  Pair(p1.bind(), p2.bind())
}

The difference is that if you bind, it would short-circuit instead of accumulating errors when any of the values is of type Invalid