Created
November 26, 2018 13:12
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| import cats.effect.concurrent.Ref | |
| import cats.effect.{IO, Sync} | |
| import cats._ | |
| import cats.implicits._ | |
| import fs2.Stream | |
| def g(r: => IO[Ref[IO, Int]]): Stream[IO, Int] = | |
| Stream | |
| .eval(r) | |
| .flatMap( | |
| x => | |
| Stream.eval(for { | |
| i <- x.get | |
| _ <- x.set(i + 1) | |
| } yield i) | |
| ) | |
| def f: Stream[IO, Int] = { | |
| val j = Ref.of[IO, Int](1) | |
| val r = for { | |
| xs <- IO(g(j)) | |
| ys <- IO(g(j)) | |
| } yield xs ++ ys | |
| Stream.eval(r).flatten | |
| } | |
| f.map(println).compile.drain.unsafeRunSync() | |
| // Result: | |
| // 1 | |
| // 1 | |
| // Desire: | |
| // 1 | |
| // 2 |
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