cats effect example as shown on dedicated typelevel site / published by https://github.com/dacr/code-examples-manager #55065ce7-79b4-4682-8f54-737227aef77b/ee0fd93bb2392fbc664dba85ad6474956e91219a

cats-learning-2-example-1-typelevel.sc

// summary : cats effect example as shown on dedicated typelevel site
// keywords : scala, cats, effect learning, pure-functional, examples
// publish : gist
// authors : typelevel, David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 55065ce7-79b4-4682-8f54-737227aef77b
// created-on : 2022-01-07T14:56:55+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.3.0"
//> using dep "org.typelevel::cats-effect:3.5.0"
// ---------------------

/*
 EXAMPLE TAKEN FROM CATS Effect home page : https://typelevel.org/cats-effect/
 As show in a PNG file : https://typelevel.org/cats-effect/img/hello-printing.png
 */

import cats.*
import cats.effect.*
import cats.effect.std.Random
import cats.effect.unsafe.implicits.global
import scala.concurrent.duration.*

object Hello extends IOApp.Simple {
  def sleepPrint(word: String, name: String, rand: Random[IO]) = for {
    delay <- rand.betweenInt(200, 700)
    _     <- IO.sleep(delay.millis)
    _     <- IO.println(s"$word, $name")
  } yield ()

  def run = for {
    rand <- Random.scalaUtilRandom[IO]
    _    <- IO.println("What is your name ?")
    name <- IO.readLine

    english <- sleepPrint("Hello", name, rand).foreverM.start
    french  <- sleepPrint("Bonjour", name, rand).foreverM.start
    spanish <- sleepPrint("Hola", name, rand).foreverM.start

    _ <- IO.sleep(5.seconds)
    _ <- english.cancel >> french.cancel >> spanish.cancel
  } yield ()
}

Hello.main(args)