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TaskBuilder: support awaiting non-generic Task and add CE helpers #2

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Merged
rexcfnghk merged 1 commit into from
Sep 8, 2025
Merged

TaskBuilder: support awaiting non-generic Task and add CE helpers #2

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1 change: 1 addition & 0 deletions DataParser.Console/Map.fs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
module Map

open System.Threading.Tasks
open Microsoft.FSharp.Control.TaskBuilder

let traverseTask (f: 'b -> Task<'c>) =
Map.fold (fun acc k v -> task {
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37 changes: 8 additions & 29 deletions DataParser.Console/TaskBuilder.fs
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Original file line number Diff line number Diff line change
@@ -1,41 +1,20 @@
[<AutoOpen>]
module TaskBuilder
namespace Microsoft.FSharp.Control

open System.Threading.Tasks

type TaskBuilder() =
type TaskBuilder () =
member _.MergeSources (x: Task<'a>, y: Task<'b>) = task {
let! _ = Task.WhenAll(x :> Task, y :> Task)
return x.Result, y.Result
}

member _.Bind(x, f) = task {
let! result = x
return! f result
member _.Bind (p: Task<'a>, k: 'a -> Task<'b>) : Task<'b> = task {
let! v = p
return! k v
}

// Bind overload to support awaiting a non-generic Task (do! someTask)
member _.Bind(x: Task, f: unit -> Task<'T>) : Task<'T> =
let tcs = new TaskCompletionSource<'T>()
x.ContinueWith(fun (t: Task) ->
if t.IsFaulted then tcs.SetException(t.Exception.InnerExceptions)
elif t.IsCanceled then tcs.SetCanceled()
else
try
let next = f()
next.ContinueWith(fun (n: Task<'T>) ->
if n.IsFaulted then tcs.SetException(n.Exception.InnerExceptions)
elif n.IsCanceled then tcs.SetCanceled()
else tcs.SetResult(n.Result)
) |> ignore
with ex -> tcs.SetException(ex)
) |> ignore
tcs.Task
member _.Return (v: 'a) : Task<'a> = Task.FromResult v

// Return helpers so the computation expression can produce tasks directly
member _.Return(x: 'T) = Task.FromResult x
member _.ReturnFrom(x: Task<'T>) = x
member _.ReturnFrom(x: Task) = x
member _.Zero() = Task.FromResult ()

let task = TaskBuilder()
module TaskBuilder =
let task = TaskBuilder()
2 changes: 1 addition & 1 deletion DataParser.Tests/DataParser.Tests.fsproj
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
<PackageReference Include="Unquote" Version="7.0.1" />
<PackageReference Include="xunit" Version="2.9.3" />
<PackageReference Include="xunit.runner.visualstudio" Version="3.1.3">
<PackageReference Include="xunit.runner.visualstudio" Version="3.1.4">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
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