Various Zio Bracketing Functions: TODO Check if these work in Dotty

LayerProject.scala

// Provide a single Environment Has clause:
// ZLayer[Orig, E, Has[From] with Rest] => ZLayer[Orig, E, Has[To] with Rest]

  def projectionWithEffect[From: Tag, To: Tag, Rest <: Has[_]: Tag, E](effect: (From, Rest) => IO[E, To]): ZLayer[Has[From] with Rest, E, Has[To] with Rest] =
    (for {
      from <- ZIO.service[From]
      rest <- ZIO.environment[Rest]
      result <- effect(from, rest)
    } yield Has(result) ++ rest).toLayerMany

  def projectWithEffectBracket[Orig: Tag, From: Tag, To: Tag, Rest <: Has[_]: Tag, E](effect: (From, Rest) => IO[E, To])(layer: ZLayer[Orig, E, Has[From] with Rest]): ZLayer[Orig, E, Has[To] with Rest] =
    layer >>> projectionWithEffect[From, To, Rest, E](effect)

LayerProjectWithBracket.scala

// Provide a single Environment Has clause with a bracketing effect:
// ZLayer[Orig, E, Has[From] with Rest] (and close To afterward) => ZLayer[Orig, E, Has[To] with Rest]

  def projectionWithManagedEffectBracket1[From: Tag, To: Tag, Rest <: Has[_]: Tag, E](managed: (Has[From] with Rest) => Managed[E, To]): ZLayer[Has[From] with Rest, E, Has[To] with Rest] =
    (for {
      fromEnv <- ZManaged.environment[Has[From]]
      restEnv <- ZManaged.environment[Rest]
      from = fromEnv.get[From]
      result <- managed(fromEnv ++ restEnv)
    } yield Has(result) ++ restEnv).toLayerMany

    def projectionWithManagedEffectBracket2[From: Tag, To: Tag, Rest <: Has[_]: Tag, E](managed: (Has[From], Rest) => Managed[E, To]): ZLayer[Has[From] with Rest, E, Has[To] with Rest] =
    (for {
      fromEnv <- ZManaged.environment[Has[From]]
      restEnv <- ZManaged.environment[Rest]
      from = fromEnv.get[From]
      result <- managed(fromEnv, restEnv)
    } yield Has(result) ++ restEnv).toLayerMany

// It would be really nice to be able to wrap the dependencies in a ZManaged that is passed in however...
// it won't work either because Scala can't figure out what 'Rest' is

  def projectionWithManagedEffectBracket1[From: Tag, To: Tag, Rest <: Has[_]: Tag, E](managed: ZManaged[Has[From] with Rest, E, To]): ZLayer[Has[From] with Rest, E, Has[To] with Rest] =
    (for {
      fromEnv <- ZManaged.environment[Has[From]]
      restEnv <- ZManaged.environment[Rest]
      from = fromEnv.get[From]
      result <- managed.provide(fromEnv ++ restEnv)
    } yield Has(result) ++ restEnv).toLayerMany

// This won't work either because Scala can't figure out what 'Rest' is

  def projectionWithManagedEffectBracket1[From: Tag, To: Tag, Rest <: Has[_]: Tag, E](managed: (Has[From] with Rest) => Managed[E, To]): ZLayer[Has[From] with Rest, E, Has[To] with Rest] =
    (for {
      fromEnv <- ZManaged.environment[Has[From]]
      restEnv <- ZManaged.environment[Rest]
      from = fromEnv.get[From]
      result <- managed(fromEnv ++ restEnv)
    } yield Has(result) ++ restEnv).toLayerMany

LayersToLayersBlockingAutoCloseable.scala

// Mapping Auto-Closeable Layers

  def mapAutoCloseableGeneric[From: Tag, To <: AutoCloseable: Tag](mapping: From => To): ZLayer[Has[From] with Blocking, Throwable, Has[To] with Blocking] = {
    val managed =
      for {
        fromBlocking <- ZManaged.environment[Has[From] with Blocking]
        from = fromBlocking.get[From]
        blocking = fromBlocking.get[Blocking.Service]
        r <- ZManaged.fromAutoCloseable(Task(mapping(from)))
      } yield Has(r) ++ Has(blocking)
    ZLayer.fromManagedMany(managed)
  }