memoize.sc

//> using dep org.typelevel::cats-effect:2.5.5
//> using dep com.lihaoyi::pprint:0.8.1
import cats.effect._
import cats.Monad
import cats.implicits._

def findParitialQuote[F[_]: Sync]: F[String] =
  Sync[F]
    .delay(pprint.pprintln("All I kept thinking about, over and over, was..."))
    .as("You can't live forever")

def completeQuote[F[_]: Monad](f: F[String]): F[String] = for {
  s <- f
  t = s + "; you can't live forever."
} yield t

import cats.effect.Sync
object main extends IOApp.Simple {
  override def run: IO[Unit] = for {
    q <- Async.memoize[IO, String](findParitialQuote)
    fs <- List.range(0, 100).map(_ => completeQuote(q).start).sequence
    _ <- fs.map(_.join).sequence
    _ <- completeQuote(q).map(pprint.pprintln(_))
  } yield ()
}

main.run.unsafeRunSync()