gistfile1.ml

#light

[<AutoOpen>]
module Operators =
  let (||>) (x,y) f = f x y

module Map =
                
  let union m1 m2 =
    (m1, m2) ||> Map.fold_right Map.add
                            
  let of_listWith (f:'a -> 'a -> 'a) (l:('key * 'a) list) : Map<'k, 'a> =
    (l, Map.empty) ||> List.fold_right 
      (fun (k, v) acc  -> 
         match Map.tryfind k acc with
         | None   -> Map.add k v acc
         | Some x -> Map.add k (f x v) acc)
         
  let singleton k v =
    Map.add k v Map.empty                                                     

let transformPrefs (m:Map<string, Map<string, float>>) =
  Map.to_list m
  |> List.map_concat (fun (x, y) -> [for (a, b) in Map.to_list y -> (a, Map.singleton x b)])
  |> Map.of_listWith Map.union