Merge branch 'main' of https://github.com/JordanMarr/FSharp.SystemCommandLine

Author: JordanMarr

README.md

@@ -153,7 +153,7 @@ let main argv =
     Recursively deleting c:\_github\FSharp.SystemCommandLine\src\FSharp.SystemCommandLine
 ```
 
-### Simple App with an Injected Dependency
+### Async App with an Injected CancellationToken
 
 `System.CommandLine` has a built-in dependency injection system and provides a handlful of built-in types that can be injected into your handler function by default:
 
@@ -170,24 +170,36 @@ You can declare injected dependencies via the `Input.InjectedDependency` method.
 module Program
 
 open FSharp.SystemCommandLine
-open System.CommandLine.Invocation
+open System.Threading
+open System.Threading.Tasks
 
-let app (ctx: InvocationContext, words: string array, separator: string option) =
-    let separator = separator |> Option.defaultValue ", "
-    System.String.Join(separator, words) |> printfn "Result: %s"
-    ctx.ExitCode <- 1
+let app (cancel: CancellationToken, words: string array, separator: string) =
+    task {
+        for i in [1..20] do
+            if cancel.IsCancellationRequested then 
+                printfn "Cancellation Requested"
+                raise (new System.OperationCanceledException())
+            else 
+                printfn $"{i}"
+                do! Task.Delay(1000)
+
+        System.String.Join(separator, words)
+        |> printfn "Result: %s"
+    }
     
 [<EntryPoint>]
 let main argv = 
-    let ctx = Input.InjectedDependency()
-    let words = Input.Option(["--word"; "-w"], Array.empty, "A list of words to be appended")
-    let separator = Input.OptionMaybe(["--separator"; "-s"], "A character that will separate the joined words.")
+    let cancel = Input.InjectedDependency()
+    let words = Input.Option(["--word"; "-w"], [||], "A list of words to be appended")
+    let separator = Input.Option(["--separator"; "-s"], ", ", "A character that will separate the joined words.")
 
     rootCommand argv {
         description "Appends words together"
-        inputs (ctx, words, separator)
+        inputs (cancel, words, separator)
         setHandler app
     }
+    |> Async.AwaitTask
+    |> Async.RunSynchronously
 ```