CE3 FiberLocal

FiberLocal.scala

import cats.effect._

trait FiberLocal[F[_], A]{

  def get: F[A]

  def set(value: A): F[Unit]

  def reset: F[Unit]

  def update(f: A => A): F[Unit]

  def modify[B](f: A => (A, B)): F[B]

  def getAndSet(value: A): F[A]

  def getAndReset: F[A]
}

trait FiberLocalGen[F[_]]{
  def create[A](default: A): F[FiberLocal[F, A]]
}

object FiberLocalGen {
  def apply[F[_]](implicit ev1: FiberLocalGen[F]): ev1.type = ev1
  
  class IOFiberLocal[F[_], A](private val ioLocal: IOLocal[A]) extends FiberLocal[IO, A]{
      def get: IO[A] = ioLocal.get

      def set(value: A): IO[Unit] = ioLocal.set(value)

      def reset: IO[Unit] = ioLocal.reset

      def update(f: A => A): IO[Unit] = ioLocal.update(f)

      def modify[B](f: A => (A, B)): IO[B] = ioLocal.modify(f)

      def getAndSet(value: A): IO[A] = ioLocal.getAndSet(value)

      def getAndReset: IO[A] = ioLocal.getAndReset
  }
  
  implicit val io: FiberLocalGen[IO] = new FiberLocalGen[IO]{
    def create[A](default: A): IO[FiberLocal[IO, A]] = IOLocal(default).map(new IOFiberLocal(_))
  }
}


import cats.effect.unsafe.implicits._
@main def example =
  FiberLocalGen[IO].create("Initial").flatMap{local =>
    local.set("Aha!") >>
    local.get.flatMap(a => IO(println(a)))
  }.unsafeRunSync()