ApplicationErrorExampleApp.scala

import cats.{Applicative, ApplicativeError}
import cats.implicits._

object ApplicationErrorExampleApp extends App {

  val f: List[Int] => Int = (xs: List[Int]) => xs.sum
  val g: List[Int] => Int = (xs: List[Int]) => xs.size

  val xs = List(List(1, 2, 3))

  Applicative[List].<*>(List(f))(xs).foreach(println)

  List(f) <*> xs

  // Using kind-projector plugin to replace the hideous type lambda syntax, 
  // ({type L[F[_]] = ApplicativeError[F, String]})#L, with a readable syntax
  def divide[F[_]: ApplicativeError[*[_], String]](a: Int, b: Int): F[Int] = if (b == 0)
    ApplicativeError[F, String].raiseError("Cannot be divided by zero")
  else ApplicativeError[F, String].pure(a / b)

  println(divide(100, 10))
  println(divide(100, 0))
}