use Incr = new Incremental()
let Var = Incr.Var
let myOrders = Var.Create([100; 150; 200])
use maxOrder = Incremental.map Incr myOrders List.max
use minOrder = Incremental.map Incr myOrders List.min
use orderRange = Incremental.map2 Incr maxOrder minOrder (-)
let log = ResizeArray<string>()
use maxChanged = maxOrder.Subscribe (fun maxOrder -> log.Add(sprintf "Max changed to %d" maxOrder))
let worldVersion = Incr.Stabilize()
Assert.AreEqual([100; 150; 200], myOrders.Value)
Assert.AreEqual(200, maxOrder.Value)
Assert.AreEqual(100, minOrder.Value)
Assert.AreEqual(100, orderRange.Value)
myOrders.SetValue([300;400;500])
Incr.Stabilize() |> ignore
Assert.AreEqual(500, maxOrder.Value)
Assert.AreEqual("Max changed to 500", Seq.last(log))