Added an overload of "Input" "GetValue" to get a parsed value from a ParseResult.

Author: JordanMarr

src/FSharp.SystemCommandLine/Inputs.fs

@@ -24,15 +24,27 @@ type HandlerInput(source: HandlerInputSource) =
 
 type HandlerInput<'T>(inputType: HandlerInputSource) =
     inherit HandlerInput(inputType)
+    
     /// Converts a System.CommandLine.Option<'T> for usage with the CommandBuilder.
     static member OfOption<'T>(o: Option<'T>) = o :> Option |> ParsedOption |> HandlerInput<'T>
+    
     /// Converts a System.CommandLine.Argument<'T> for usage with the CommandBuilder.
     static member OfArgument<'T>(a: Argument<'T>) = a :> Argument |> ParsedArgument |> HandlerInput<'T>
+
+    /// Gets the value of an Option or Argument from the InvocationContext.
     member this.GetValue(ctx: System.CommandLine.Invocation.InvocationContext) =
         match this.Source with
         | ParsedOption o -> o :?> Option<'T> |> ctx.ParseResult.GetValueForOption
         | ParsedArgument a -> a :?> Argument<'T> |> ctx.ParseResult.GetValueForArgument
         | Context -> ctx |> unbox<'T>
+    
+    /// Gets the value of an Option or Argument from the Parser.
+    member this.GetValue(parseResult: Parsing.ParseResult) =
+        match this.Source with
+        | ParsedOption o -> o :?> Option<'T> |> parseResult.GetValueForOption
+        | ParsedArgument a -> a :?> Argument<'T> |> parseResult.GetValueForArgument
+        | Context -> failwith "Cannot get a value for InvocationContext from a ParseResult."
+
 
 let private applyConfiguration configure a = 
     configure a; a

src/TestConsole/ProgramNestedSubCommands.fs

@@ -3,6 +3,7 @@
 open System.IO
 open FSharp.SystemCommandLine
 open System.CommandLine.Invocation
+open System.CommandLine.Parsing
 
 module Global = 
     let enableLogging = Input.Option<bool>("--enable-logging", false)
@@ -70,9 +71,20 @@ let ioCmd =
 
 //[<EntryPoint>]
 let main argv =
-    rootCommand argv {
-        description "Sample app for System.CommandLine"
-        setHandler id
-        addGlobalOptions Global.options
-        addCommand ioCmd
-    }
+    let ctx = Input.Context()
+    
+    let parser = 
+        rootCommandParser {
+            description "Sample app for System.CommandLine"
+            setHandler id
+            addGlobalOptions Global.options
+            addCommand ioCmd
+        }
+
+    let parseResult = parser.Parse(argv)
+
+    let loggingEnabled = Global.enableLogging.GetValue parseResult
+    printfn $"ROOT: Logging enabled: {loggingEnabled}"
+
+    parseResult.Invoke()
+