带有块和任务的 Scala fs2 流？

Question

  // Simulated external API that synchronously returns elements one at a time indefinitely.
  def externalApiGet[A](): A = ???

  // This wraps with the proper fs2 stream that will indefinitely return values.
  def wrapGetWithFS2[A](): Stream[Task, A] = Stream.eval(Task.delay(externalApiGet))

  // Simulated external API that synchronously returns "chunks" of elements at a time indefinitely.
  def externalApiGetSeq[A](): Seq[A] = ???

  // How do I wrap this with a stream that hides the internal chunks and just provides a stream of A values.
  // The following doesn't compile. I need help fixing this.
  def wrapGetSeqWithFS2[A](): Stream[Task, A] = Stream.eval(Task.delay(externalApiGetSeq))

Answer 1

您需要将序列标记为 Chunk，然后使用 flatMap 来展平流。

def wrapGetSeqWithFS2[A](): Stream[Task, A] =
  Stream.eval(Task.delay(externalApiGetSeq()))
    .flatMap(Stream.emits)

（已编辑以简化解决方案）

带有块和任务的 Scala fs2 流？

Scala fs2 Streams with Chunks and Tasks?

scala

scalaz-stream

fs2