DuckTyping.fs

(* Duck Typing *)

let inline flyAndWalk arg =
  let flying = ( ^a : (member Fly : unit -> string) arg)
  let walking = ( ^a : (member Walk : unit -> string) arg)
  (flying, walking)

type Duck() =
  member this.Swim() = "paddling"
  member this.Fly() = "flapping"
  member this.Walk() = "waddling"
 
type Eagle() =
  member this.Fly() = "soaring"
  member this.Walk() = "creeping"
 
let (eFly, eWalk) = flyAndWalk (new Eagle())
let (dFly, dWalk) = flyAndWalk (new Duck())