<@UJHCLJVUK> the one from my scratch pad is this: ...

# arrow

[tim]

@julian the one from my scratch pad is this:

val a = Either.right(1)
val b = Either.right(2)
val c = Either.right(3)

val d = Either
    .applicative<Nothing>()
    .mapN(a, b, c) { (a, b, c) ->
        listOf(a, b, c)
    }
    .fix()
    .fold(
        ifLeft = { println("try again :(") },
        ifRight = { println("success: $it") }
    )

But I'm now integrating it into my actual use case which is about parsing variables from a url path

[julian]

Thanks @tim!

[tim]

Hmm I've tried to expand this a bit but no joy:

val a = getEither(1)
val b = getEither(2)
val c = getEither(3)

val d = Either
    .applicative<Int>()
    .mapN(a, b, c) { (a, b, c) ->
        listOf(a, b, c)
    }
    .fix()
    .fold(
        ifLeft = { println("try again :(") },
        ifRight = { println("success: $it") }
    )

fun getEither(value: Int) : Either<String, Int> {
    return if(Random.nextBoolean()) {
        Either.left("ouch!")
    } else {
        Either.right(value)
    }
}

[tim]

I'm getting this .. its fine with Left = Nothing

[pakoito]

^^^

That last one is Either.conditionally

[pakoito]

that warning, if you squint

[pakoito]

is telling you you’re expecting string on the left

[pakoito]

and the applicative expects Int on the left instead

[tim]

Ahhh

[tim]

So whats in applicative is the Left value of the either

[tim]

haha yep that fixed it straight away thanks!

[tim]

I'll adjust my original code above as that's not correct then