Hi, what would be the alternative for `option.fx {...

# arrow

[carbaj0]

Hi, what would be the alternative for option.fx {} ?
this cannot be achieved with nullable, right?
should I replace it with either.fx { }?

[carbaj0]

class DebitCardNumber private constructor(
    val number: String
) {
    companion object {
        private const val Mastercard = "^(?:5[1-5][0-9]{2}|222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}\$"

        suspend operator fun invoke(number: String): Either<Unit, DebitCardNumber> =
            if (number.matches(Mastercard.toRegex())) DebitCardNumber(number).right() else Unit.left()
    }
}

[carbaj0]

IO.fx {
            val validCardNumber = !effect { DebitCardNumber(cardNumber) }
            Either.fx<Unit, DebitCard> {
                VirtualDebitCard(
                    cardNumber = !validCardNumber,
                    accountNumber = accountNumber ?: "",
                    contractNumber = contractNumber ?: "",
                    cardStatus = cardStatus ?: "",
                    cancelIndicator = cancelReason ?: "",
                    cancelReason = cancelIndicator ?: "",
                    cardAlias = cardAlias ?: ""
                )
            }

        }.suspended()

[simon.vergauwen]

It can be achieved for nullable, and someone is contributing it 🙂 https://github.com/arrow-kt/arrow-core/pull/251

[carbaj0]

sealed class Shift<out T>
object Empty : Shift<Nothing>()
data class Result<T>(val result: T) : Shift<T>()

[carbaj0]

is this wrap needed?

[kioba]

No, that wrap will be eliminated in the next commit, the guys helped me how to avoid this scenario, which means no wrapping performance penalty for continuation.

[carbaj0]

👍