InjectionTest.fsx

type Input =
    | ResultGreat
    | ResultNotSoGreat

type ResultImproverAgent (logger) = 
    let agent = MailboxProcessor.Start(fun inbox -> 
            let rec messageLoop () = async {
                let! msg =  inbox.Receive()
                match msg with
                | ResultGreat -> "Result already great, cannot be improved" |> logger 
                | ResultNotSoGreat -> "Result is not so great, putting it in the backlog" |> logger
                return! messageLoop ()
                }
            messageLoop ()
        )

    member this.Post msg = agent.Post msg


type SomeAgent (logger, improveAgent) = 
    let agent = MailboxProcessor.Start(fun inbox -> 
            let rec messageLoop () = async {
                let! msg =  inbox.Receive()
                match msg with
                | ResultGreat -> "Nothin more todo, result is great!" |> logger
                | ResultNotSoGreat -> "Result bad, sending it to be improved" |> logger
                                      msg |> improveAgent
                return! messageLoop ()
                }
            messageLoop ()
        )

    member this.Post msg = agent.Post msg


let Orchastrator () =
    let log input =
        input |> printfn "%s" 
    let improverAgent = ResultImproverAgent log
    let someAgent = SomeAgent (log, improverAgent.Post)
    
    ResultNotSoGreat |> someAgent.Post
    0

Orchastrator()