and this ```val result = either<Throwable, Int&...

# arrow

[Jörg Winter]

and this

val result = either<Throwable, Int> {
    val allEmployees: List<Employee> = allEmployees()()
    val greetings: List<EmailMessage> = birthdayMessages(allEmployees, date)()
    val results: List<String> = greetings.parTraverseEither(<http://Dispatchers.IO|Dispatchers.IO>) {
        println("before")
        val greeting = sendGreeting(it)
        println("after")
        greeting
    }()
    results.map { println(it); 1 }.sum()
}

has no output before or after

[pakoito]

greetings.length is then > 0…just ruling out the most obvious ones (edited) 

[11:33 PM] it may be that allEmployees or birthdayMessages are failing or something
[11:33 PM] actually, printing the result of env.sendGreetingsUseCase(date = LocalDate.now())  may help
[11:34 PM] whether it’s left or right, if the program finishes it’ll give us information

[Jörg Winter]

Hi, no printing anywhere changes anything... it's an empty list from

[Jörg Winter]

greetings.parTraverseEither(<http://Dispatchers.IO|Dispatchers.IO>)

... but I am not sure: can we actually pass kotlinx.coroutines.Dispatchers here ?

[simon.vergauwen]

Yes, you can. I wrote some extra docs, and tests in this PR. Seems to run fine. What the value of greetings?

https://github.com/arrow-kt/arrow-fx/pull/355

[Jörg Winter]

@simon.vergauwen it's working as expected, ...I was blind 😔
This style of effectful computations is great !
I also noticed parTraverse... fpr Validated in your PR ... will try that too.
arrow💯

[pakoito]

what was the problem then? I’m confused xD

[Jörg Winter]

short circuiting before even reaching parTraverse, sorry for the confusion 😔