Lift function example 1

lift_example1.scala

import scala.util.Try

// Allows a function A => B to operate on options

def lift[A, B](f: A => B): Option[A] => Option[B] = _ map f //(a: Option[A]) => a.map(f)

val cbrtO: Option[Double] => Option[Double] = lift(math.cbrt)

val r1 = Try(throw new RuntimeException).toOption
val r2 = Try(1000d).toOption

cbrtO(r1) // res0: Option[Double] = None
cbrtO(r2) // res1: Option[Double] = Some(10.0)


// Another example

def map2[A, B, C](a: Option[A], b: Option[B])(f: (A, B) => C): Option[C] =
  a.flatMap(aa => b.map(bb => f(a, b)))

def bar(a: Int, b: Int) = a * b

def foo(a: String, b: String): Option[Int] = {
  val aOpt: Option[Int] = Try(a.toInt).toOption
  val bOpt: Option[Int] = Try(b.toInt).toOption
  map2(aOpt, bOpt)(bar)