<https://github.com/arrow-kt/arrow-fx/blob/32d3d45...

# arrow

[pakoito]

https://github.com/arrow-kt/arrow-fx/blob/32d3d45d530f4dfddbf7f114f3cbc39d801491a3/arrow-fx/src/main/kotlin/arrow/fx/typeclasses/Concurrent.kt#L464

[Attila Domokos]

Would that work with arrow.fx.coroutines?

[pakoito]

hmmmm I don’t believe it does

[pakoito]

so, nest them for now?

[Attila Domokos]

Or should I add a PR to expand the arity to 5?

[Attila Domokos]

Others might bump into the same issue challenge.

[HieiJ]

As suggested by @pakoito, you can nest multiple calls to parMapN in order to get the arity you need:

suspend fun <A, B, C, D, E> parMapN(fa: suspend () -> A,
                                    fb: suspend () -> B,
                                    fc: suspend () -> C,
                                    fd: suspend () -> D,
                                    f: (a:A, b:B, c:C, d:D) -> E) {
  val temp1 = suspend { parMapN(fa, fb, ::identity) }
  val temp2 = suspend { parMapN(fc, fd, ::identity)  }
  parMapN(temp1, temp2) { (t1, t2) -> f(t1.first, t1.second, t2.first, t2.second) }
}

[HieiJ]

you can also inline temp1 and temp2 and the suspend modifier is inferred:

parMapN(
    { parMapN(fa, fb, ::identity) },
    { parMapN(fc, fd, ::identity)  }) { (t1, t2) ->
    f(t1.first, t1.second, t2.first, t2.second)
  }

[Attila Domokos]

@HieiJ - thanks for the suggestion, that is exactly what I am doing. But the complexity is much higher with that approach.