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intermediate updates for a long running function
f#

I'm looking to postback updates as a recursive function runs.

Right now, I've got something like this:

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let rec myFun checkPoint a n =

    // ...

    checkPoint a n |> Async.Spawn

    // ...

  myFun checkPoint a (n+1)

which works good when all I'm doing is updating a text file. But, this isn't really general, and I don't think I could update a GUI.

I'm wondering if I should be using an event (or something else?).

I suppose I could use a regular function. But, that just moves the problem, I think.

.

I ended up using MailboxProcessor. Somewhat like the example in Expert F#.

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open Microsoft.FSharp.Control

type Message<'a> =

 | Die // quit

    | Fetch of MailboxProcessor<'a> // get the current state

    | Deliver of 'a // replace the current state

    //| Some of int

    

let interactiveFunction f f_zero =

    MailboxProcessor.Start(fun inbox ->

        let rec loop x =

            async {

                //let! msg = inbox.Receive()

                let! tryMsg = inbox.TryReceive(timeout=0)

                match tryMsg with

                    | None ->

                        //printfn "loop %d" x

                        return! loop (f x)

                    | Some msg ->

                        match msg with

                            | Die -> ()

                            | Fetch replyChannel ->

                                //printfn "Fetch %d" x

                                // post response to reply channel and continue

                                do replyChannel.Post(x)

                                return! loop (f x) 

                            | Deliver m ->

                                //printfn "Deliver %d" m

                                //printfn "Replace %d" x

                                return! loop m

                }

        loop f_zero)
By on 4/9/2009 7:35 AM ()

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