Added AcceptLegalFilePathsOnly

Author: mrboring

README.md

@@ -72,6 +72,7 @@ The new `Input` module contains functions for the underlying System.CommandLine
 * `optionMaybe` creates a named `Option<'T option>` that defaults to `None`.
 
 ### Input Properties
+* `acceptLegalFilePathsOnly` sets the option or argument to accept only values representing legal file paths.
 * `alias` adds an `Alias` to an `Option`
 * `aliases` adds one or more aliases to an `Option`
 * `desc` adds a description to an `Option` or `Argument`

src/FSharp.SystemCommandLine/Inputs.fs

@@ -68,6 +68,12 @@ module Input =
         | _ -> ()
         input
 
+    /// Configures the option or argument to accept only values representing legal file paths.
+    let acceptLegalFilePathsOnly (input: ActionInput<'T>) =
+        input
+        |> editOption (fun o -> o.AcceptLegalFilePathsOnly() |> ignore)
+        |> editArgument (fun a -> a.AcceptLegalFilePathsOnly() |> ignore)
+
     /// Adds one or more aliases to an option.
     let aliases (aliases: string seq) (input: ActionInput<'T>) = 
         input |> editOption (fun o -> aliases |> Seq.iter o.Aliases.Add)