       unsub
     resultProperty = new Property describe(this, "scan", seed, f), subscribe
 
-  fold: (seed, f) =>
+  fold: (seed, f) ->
     withDescription(this, "fold", seed, f, @scan(seed, f).sampledBy(@filter(false).mapEnd().toProperty()))
 
   zip: (other, f = Array) ->

        if reply == Bacon.noMore
          return reply
      reply
  scan: (seed, f, lazyF) =>
    f_ = toCombinator(f)
    f = if lazyF then f_ else (x,y) -> f_(x(), y())
    acc = toOption(seed).map((x) -> _.always(x))
    root = this
    subscribe = (sink) =>
      initSent = false
      unsub = nop

          sink(e)
      -> unsubLeft() ; unsubRight()

  takeUntil: (stopper) ->
    endMarker = {}
    withDescription(this, "takeUntil", stopper, Bacon.groupSimultaneous(this.mapEnd(endMarker), stopper.skipErrors())
      .withHandler((event) ->
