traverse3.kt

fun demoTraverse(input: List<String>) {
    val failure = { error: String -> println(error) }
    val success = { results: List<String> ->
        println("Results are:")
        results.map { s -> "\t$s" }
            .forEach(::println)
    }

    val result = input.traverse(Either.applicative(), ::propertyViaJVM)
    result.fix()
        .fold(failure) { success(it.fix()) }
}

in Arrow 0.12 this looks like this

    val result: Either<String, List<String>> = input.traverseEither(::propertyViaJVM)
    result.fold(failure) { success(it) }

even more nice for the enterprise bees ;)