Using Arrow 1.2.0-RC, what's the most elegant way to handle something like this?

val squares = (1..10).mapOrAccumulate { squareService.square(it).bind() } // EitherNel<E1, Square>
val roots = (1..10).mapOrAccumulate { rootService.root(it).bind() } // EitherNel<E2, Root>

zipOrAccumulate(
  { // check squares? },
  { // check roots? },
  { ensureSomethingElse() },
) { validSquares, validRoots, somethingElse -> 
   // ... 
}

So you need to align E1 and E2? Otherwise you can just call

bind

yes, I thought I'd do that

With

Either

I would just use

mapLeft + bind

.

val squares = (1..10).mapOrAccumulate { squareService.square(it).bind() } // EitherNel<E1, Square>
val roots = (1..10).mapOrAccumulate { rootService.root(it).bind() } // EitherNel<E2, Root>

zipOrAccumulate(
  { squares.mapLeft { }.bind() },
  { roots.mapLeft { }.bind() },
  { ensureSomethingElse() },
) { validSquares, validRoots, somethingElse -> 
   // ... 
}

Thanks Simon 🙌