conditions.fsx

#!/usr/bin/env fsharpi

#I "../../../.nuget/packages/hopac/0.3.21/lib/net45/"
#I "../../../.nuget/packages/hopac.extras/0.3.1/lib/net45"
#r "Hopac.Extras"
#r "Hopac.Platform"
#r "Hopac.Core"
#r "Hopac"

open System
open System.Collections.Generic

open Hopac.Job
open Hopac
open Hopac.Infixes
open Hopac.Extensions


[<Sealed>]
type Condition() =
    let mutable subs: IVar<unit> list = []

    member this.wait () =
        let v = IVar<unit> ()
        subs <- (List.rev subs) |> fun x -> v :: x |> List.rev
        IVar.read v

    member this.signal () =
        if subs.Length > 0 then
            for v in subs do
                start (IVar.fill v ())
            subs <- []

let c = Condition()
let q = Condition()

let bg i = job {
    do printfn "client %i ..." i
    do! c.wait()
    do printfn "client %i <==" i
    do printfn "client %i==>" i
    do q.signal()
    }

start (conIgnore [ for i in [1..3] do yield bg i])

run (delay (fun _ -> job {
    do printfn "server ..."
    do! timeOut (TimeSpan.FromSeconds 2.0)
    do printfn "server ==>"
    do c.signal()
    do printfn "server ..."
    do! q.wait()
    do printfn "server <=="
    }))

output.txt

 ./channel-test.fsx
server ...
client 2 ...
client 1 ...
client 3 ...
server ==>
server ...
client 3 <==
client 2 <==
client 1 <==
client 3==>
client 2==>
client 1==>
server <==