Blog-AOCD1P1-Turn2.fs

let turn way loc = 
  match way with
  | L -> 
    match loc.dir with
    | North -> { loc with dir = West }
    | West -> { loc with dir = South }
    | South -> { loc with dir = East }
    | East -> { loc with dir = North }
  | R ->
    match loc.dir with
    | North -> { loc with dir = East }
    | East -> { loc with dir = South } 
    | South -> { loc with dir = West }
    | West -> { loc with dir = North }