Better user input helper

src/app/FakeLib/UserInputHelper.fs

@@ -4,30 +4,55 @@ module Fake.UserInputHelper
 
 open System
 
+let internal erasePreviousChar () =
+ try
+ let left = if Console.CursorLeft <> 0 then Console.CursorLeft-1 else Console.BufferWidth-1
+ let top = if Console.CursorLeft <> 0 then Console.CursorTop else Console.CursorTop-1
+
+ Console.SetCursorPosition(left, top)
+ Console.Write(' ')
+ Console.SetCursorPosition(left, top) 
+ with
+ | :? IO.IOException ->
+ // Console is dumb, might be redirected. We don't care,
+ // if it isn't a screen the visual feedback isn't required
+ ()
+
 let internal readString (echo: bool) : string =
  let rec loop cs =
- let key = Console.ReadKey(not echo)
- match key.Key with
- | ConsoleKey.Backspace -> match cs with
- | [] -> loop []
- | _::cs -> loop cs
- | ConsoleKey.Enter -> cs
- | _ -> loop (key.KeyChar :: cs)
-
+ let key = Console.ReadKey(true)
+ match (key.Key, cs) with
+ | (ConsoleKey.Backspace, []) -> loop []
+ | (ConsoleKey.Backspace, _::cs) -> 
+ erasePreviousChar ()
+ loop cs
+ | (ConsoleKey.Enter, _) -> cs
+ | _ ->
+ if echo then Console.Write(key.KeyChar) else Console.Write('*')
+ loop (key.KeyChar :: cs)
+
  loop []
  |> List.rev
  |> Array.ofList
  |> fun cs -> new String(cs)
 
+let internal color (color: ConsoleColor) (code : unit -> _) =
+ let before = Console.ForegroundColor
+ Console.ForegroundColor <- color
+ let result = code ()
+ Console.ForegroundColor <- before
+ result
+
 /// Return a string entered by the user followed by enter. The input is echoed to the screen.
 let getUserInput prompt =
- printf "%s" prompt
- readString true
+ color ConsoleColor.White (fun _ -> printf "%s" prompt)
+ let s = readString true
+ printfn ""
+ s
 
-/// Return a string entered by the user followed by enter. The input is not echoed to the screen.
+/// Return a string entered by the user followed by enter. The input is replaced by '*' on the screen.
 let getUserPassword prompt =
- printf "%s" prompt
+ color ConsoleColor.White (fun _ -> printf "%s" prompt)
  let s = readString false
  printfn ""
  s
-