How to combine Option values in Scala?

Question

I want to be able to apply an operation f: (T,T) => T to Option[T] values in Scala. I want the result to be None if any of the two

Answer 1

I have a slightly older version of scalaz than retronym but the following works for me as an example and is generalizable for the case where you have 3 types T, U, V and not just one:

def main(args: Array[String]) {
  import scalaz._
  import Scalaz._

  val opt1 = some(4.0) //Option[Double]
  val opt2 = some(3)   //Option[Int]

  val f: (Double, Int) => String = (d, i) => "[%d and %.2f]".format(i, d)

  val res = (opt1 <|*|> opt2).map(f.tupled)
  println(res) //Some([3 and 4.00])
}

I can then add:

val opt3 = none[Int]
val res2 = (opt1 <|*|> opt3).map(f.tupled)
println(res2) //None