gistfile1.ml

#light

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

module Map =
  let transposeCombine m =
    (Map.empty, m) ||> Map.fold_left (fun acc k1 m' ->
      (acc, m') ||> Map.fold_left (fun acc' k2 v ->
        acc'
        |> Map.add k1 (Map.add k2 v (defaultArg (acc' |> Map.tryfind k1) Map.empty))
        |> Map.add k2 (Map.add k1 v (defaultArg (acc' |> Map.tryfind k2) Map.empty))
    ))

type City = 
    | Boise     | LosAngeles    | NewYork   | Seattle
    | StLouis   | Phoenix       | Boston    | Chicago   
    | Denver
    
let distTweenCities = 
  Map.of_list
    [
        (Boise, Map.of_list [(Seattle, 496);(Denver,  830);(Chicago, 1702)]);    
        (Seattle, Map.of_list [(LosAngeles, 1141);(Denver,  1321)]);     
        (LosAngeles, Map.of_list [(Denver,  1022);(Phoenix, 371)]);  
        (Phoenix, Map.of_list [(Denver,  809);(StLouis, 1504)]);      
        (Denver,  Map.of_list [(StLouis, 588);(Chicago, 1009)]);     
        (Chicago, Map.of_list [(NewYork, 811);(Boston,  986)]);      
        (StLouis, Map.of_list [(Chicago, 300)]);
        (Boston, Map.of_list [(StLouis,  986)]);      
        (NewYork, Map.of_list [(Boston,  211)])
    ]
    |> Map.transposeCombine
    
let printValues (m:Map<City, Map<City, int>>) =
  m |> Seq.iter(fun kvp -> printf "%A\t" kvp.Key; kvp.Value |> Seq.iter(fun kvp' -> printf "%A\t%d" kvp'.Key kvp'.Value); printfn "")