Monads.scala

import scala.util.{Failure, Success, Try}

val f1: (Int) => Try[String] = x => Try(s"f1($x)")
val f2: (String) => Try[String] = y => Try(s"f2($y)")
val f3: (String) => Try[String] = z => Try(s"f3($z)")

val x = 10
val res: Try[String] = f1(x).flatMap(y => f2(y).flatMap(z => f3(z)))
println(res)
// Success(f3(f2(f1(10))))

val res2: Try[String] = f1(x) match {
  case Success(y) => f2(y) match {
    case Success(z) => f3(z)
    case e2@Failure(_) => e2
  }
  case e1@Failure(_) => e1
}
println(res2)
// Success(f3(f2(f1(10))))