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Async Workflow support for Task operations

Simple Async Workflow computation expression overload to support task operations.

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open System.Threading.Task

type AsyncBuilder with
  member x.Bind(task : Task<'a>, f : 'a -> Async<'b>) =
    let task = task |> Async.AwaitTask
    async.Bind(task, f)


// Example
let work = async {
        use client = new System.Net.WebClient()
        let! bytes = client.DownloadDataTaskAsync(Uri("http://www.google.com"))  
        do! Task.Factory.StartNew<unit>(fun () -> File.WriteAllBytes(@"c:\temp\google.bin", bytes))

        do! Task.Run<unit>(fun () -> printfn "Bytes len %d" bytes.Length)

        return bytes } |> Async.RunSynchronously

printfn "first 5 Bytes %A" work.[0..4]
namespace System
namespace System.Threading
type AsyncBuilder =
  private new : unit -> AsyncBuilder
  member Bind : computation:Async<'T> * binder:('T -> Async<'U>) -> Async<'U>
  member Combine : computation1:Async<unit> * computation2:Async<'T> -> Async<'T>
  member Delay : generator:(unit -> Async<'T>) -> Async<'T>
  member For : sequence:seq<'T> * body:('T -> Async<unit>) -> Async<unit>
  member Return : value:'T -> Async<'T>
  member ReturnFrom : computation:Async<'T> -> Async<'T>
  member TryFinally : computation:Async<'T> * compensation:(unit -> unit) -> Async<'T>
  member TryWith : computation:Async<'T> * catchHandler:(exn -> Async<'T>) -> Async<'T>
  member Using : resource:'T * binder:('T -> Async<'U>) -> Async<'U> (requires 'T :> IDisposable)
  ...

Full name: Microsoft.FSharp.Control.AsyncBuilder
val x : AsyncBuilder
member AsyncBuilder.Bind : task:System.Threading.Tasks.Task<'a> * f:('a -> Async<'b>) -> Async<'b>

Full name: Script.Bind
val task : System.Threading.Tasks.Task<'a>
val f : ('a -> Async<'b>)
Multiple items
type Async
static member AsBeginEnd : computation:('Arg -> Async<'T>) -> ('Arg * AsyncCallback * obj -> IAsyncResult) * (IAsyncResult -> 'T) * (IAsyncResult -> unit)
static member AwaitEvent : event:IEvent<'Del,'T> * ?cancelAction:(unit -> unit) -> Async<'T> (requires delegate and 'Del :> Delegate)
static member AwaitIAsyncResult : iar:IAsyncResult * ?millisecondsTimeout:int -> Async<bool>
static member AwaitTask : task:Task -> Async<unit>
static member AwaitTask : task:Task<'T> -> Async<'T>
static member AwaitWaitHandle : waitHandle:WaitHandle * ?millisecondsTimeout:int -> Async<bool>
static member CancelDefaultToken : unit -> unit
static member Catch : computation:Async<'T> -> Async<Choice<'T,exn>>
static member FromBeginEnd : beginAction:(AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg:'Arg1 * beginAction:('Arg1 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * beginAction:('Arg1 * 'Arg2 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromBeginEnd : arg1:'Arg1 * arg2:'Arg2 * arg3:'Arg3 * beginAction:('Arg1 * 'Arg2 * 'Arg3 * AsyncCallback * obj -> IAsyncResult) * endAction:(IAsyncResult -> 'T) * ?cancelAction:(unit -> unit) -> Async<'T>
static member FromContinuations : callback:(('T -> unit) * (exn -> unit) * (OperationCanceledException -> unit) -> unit) -> Async<'T>
static member Ignore : computation:Async<'T> -> Async<unit>
static member OnCancel : interruption:(unit -> unit) -> Async<IDisposable>
static member Parallel : computations:seq<Async<'T>> -> Async<'T []>
static member RunSynchronously : computation:Async<'T> * ?timeout:int * ?cancellationToken:CancellationToken -> 'T
static member Sleep : millisecondsDueTime:int -> Async<unit>
static member Start : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions * ?cancellationToken:CancellationToken -> Task<'T>
static member StartChild : computation:Async<'T> * ?millisecondsTimeout:int -> Async<Async<'T>>
static member StartChildAsTask : computation:Async<'T> * ?taskCreationOptions:TaskCreationOptions -> Async<Task<'T>>
static member StartImmediate : computation:Async<unit> * ?cancellationToken:CancellationToken -> unit
static member StartWithContinuations : computation:Async<'T> * continuation:('T -> unit) * exceptionContinuation:(exn -> unit) * cancellationContinuation:(OperationCanceledException -> unit) * ?cancellationToken:CancellationToken -> unit
static member SwitchToContext : syncContext:SynchronizationContext -> Async<unit>
static member SwitchToNewThread : unit -> Async<unit>
static member SwitchToThreadPool : unit -> Async<unit>
static member TryCancelled : computation:Async<'T> * compensation:(OperationCanceledException -> unit) -> Async<'T>
static member CancellationToken : Async<CancellationToken>
static member DefaultCancellationToken : CancellationToken

Full name: Microsoft.FSharp.Control.Async

--------------------
type Async<'T>

Full name: Microsoft.FSharp.Control.Async<_>
val task : Async<'a>
static member Async.AwaitTask : task:System.Threading.Tasks.Task -> Async<unit>
static member Async.AwaitTask : task:System.Threading.Tasks.Task<'T> -> Async<'T>
val async : AsyncBuilder

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.async
member AsyncBuilder.Bind : task:System.Threading.Tasks.Task<'a> * f:('a -> Async<'b>) -> Async<'b>
member AsyncBuilder.Bind : computation:Async<'T> * binder:('T -> Async<'U>) -> Async<'U>
val work : obj

Full name: Script.work
val client : System.Net.WebClient
namespace System.Net
Multiple items
type WebClient =
  inherit Component
  new : unit -> WebClient
  member BaseAddress : string with get, set
  member CachePolicy : RequestCachePolicy with get, set
  member CancelAsync : unit -> unit
  member Credentials : ICredentials with get, set
  member DownloadData : address:string -> byte[] + 1 overload
  member DownloadDataAsync : address:Uri -> unit + 1 overload
  member DownloadFile : address:string * fileName:string -> unit + 1 overload
  member DownloadFileAsync : address:Uri * fileName:string -> unit + 1 overload
  member DownloadString : address:string -> string + 1 overload
  ...

Full name: System.Net.WebClient

--------------------
System.Net.WebClient() : unit
val bytes : obj
type unit = Unit

Full name: Microsoft.FSharp.Core.unit
val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn
static member Async.RunSynchronously : computation:Async<'T> * ?timeout:int * ?cancellationToken:System.Threading.CancellationToken -> 'T
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More information

Link:http://fssnip.net/7Py
Posted:1 years ago
Author:Riccardo Terrell
Tags: async , computation expression , task