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Agent demo

Agent demo

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type Agent<'T> = MailboxProcessor<'T>

/// Represents different messages 
/// handled by the stats agent
type StatsMessage = 
  | Add of float
  | Clear
  | GetAverage of AsyncReplyChannel<float>

let stats = 
  Agent.Start(fun inbox ->
    
    // Loops, keeping a list of numbers
    let rec loop nums = async {
      let! msg = inbox.Receive()
      match msg with 
      | Add num ->
          let newNums = num::nums
          return! loop newNums 
      | GetAverage repl ->
          repl.Reply(List.average nums)
          return! loop nums
      | Clear ->
          return! loop [] }    

    loop [] )

// Add error handler
stats.Error.Add(fun e -> printfn "Oops: %A" e)

// Post messages
stats.Post(Add(10.0))
stats.Post(Add(7.0))
stats.Post(Clear)
stats.PostAndReply(GetAverage)

(*

Chat room message:

 * NewMessage with name and text
 * GetAllMessages returns all messages 
   via AsyncReplyChannel

*)
Multiple items
type MailboxProcessor<'Msg> =
  interface IDisposable
  new : body:(MailboxProcessor<'Msg> -> Async<unit>) * ?cancellationToken:CancellationToken -> MailboxProcessor<'Msg>
  member Post : message:'Msg -> unit
  member PostAndAsyncReply : buildMessage:(AsyncReplyChannel<'Reply> -> 'Msg) * ?timeout:int -> Async<'Reply>
  member PostAndReply : buildMessage:(AsyncReplyChannel<'Reply> -> 'Msg) * ?timeout:int -> 'Reply
  member PostAndTryAsyncReply : buildMessage:(AsyncReplyChannel<'Reply> -> 'Msg) * ?timeout:int -> Async<'Reply option>
  member Receive : ?timeout:int -> Async<'Msg>
  member Scan : scanner:('Msg -> Async<'T> option) * ?timeout:int -> Async<'T>
  member Start : unit -> unit
  member TryPostAndReply : buildMessage:(AsyncReplyChannel<'Reply> -> 'Msg) * ?timeout:int -> 'Reply option
  ...

Full name: Microsoft.FSharp.Control.MailboxProcessor<_>

--------------------
new : body:(MailboxProcessor<'Msg> -> Async<unit>) * ?cancellationToken:System.Threading.CancellationToken -> MailboxProcessor<'Msg>
type StatsMessage =
  | Add of float
  | Clear
  | GetAverage of AsyncReplyChannel<float>

Full name: Script.StatsMessage


 Represents different messages
 handled by the stats agent
union case StatsMessage.Add: float -> StatsMessage
Multiple items
val float : value:'T -> float (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.float

--------------------
type float = System.Double

Full name: Microsoft.FSharp.Core.float

--------------------
type float<'Measure> = float

Full name: Microsoft.FSharp.Core.float<_>
union case StatsMessage.Clear: StatsMessage
union case StatsMessage.GetAverage: AsyncReplyChannel<float> -> StatsMessage
type AsyncReplyChannel<'Reply>
member Reply : value:'Reply -> unit

Full name: Microsoft.FSharp.Control.AsyncReplyChannel<_>
val stats : MailboxProcessor<StatsMessage>

Full name: Script.stats
type Agent<'T> = MailboxProcessor<'T>

Full name: Script.Agent<_>
static member MailboxProcessor.Start : body:(MailboxProcessor<'Msg> -> Async<unit>) * ?cancellationToken:System.Threading.CancellationToken -> MailboxProcessor<'Msg>
val inbox : MailboxProcessor<StatsMessage>
val loop : (float list -> Async<'a>)
val nums : float list
val async : AsyncBuilder

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.async
val msg : StatsMessage
member MailboxProcessor.Receive : ?timeout:int -> Async<'Msg>
val num : float
val newNums : float list
val repl : AsyncReplyChannel<float>
member AsyncReplyChannel.Reply : value:'Reply -> unit
Multiple items
module List

from Microsoft.FSharp.Collections

--------------------
type List<'T> =
  | ( [] )
  | ( :: ) of Head: 'T * Tail: 'T list
  interface IEnumerable
  interface IEnumerable<'T>
  member Head : 'T
  member IsEmpty : bool
  member Item : index:int -> 'T with get
  member Length : int
  member Tail : 'T list
  static member Cons : head:'T * tail:'T list -> 'T list
  static member Empty : 'T list

Full name: Microsoft.FSharp.Collections.List<_>
val average : list:'T list -> 'T (requires member ( + ) and member DivideByInt and member get_Zero)

Full name: Microsoft.FSharp.Collections.List.average
event MailboxProcessor.Error: IEvent<Handler<System.Exception>,System.Exception>
member System.IObservable.Add : callback:('T -> unit) -> unit
val e : System.Exception
val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn
member MailboxProcessor.Post : message:'Msg -> unit
member MailboxProcessor.PostAndReply : buildMessage:(AsyncReplyChannel<'Reply> -> 'Msg) * ?timeout:int -> 'Reply
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More information

Link:http://fssnip.net/nQ
Posted:3 years ago
Author:Tomas Petricek
Tags: async