Experimenting with Elm Dictionaries

dict.elm

import Html exposing (text, div, br)
import Dict exposing (Dict)

times3 : Maybe Int -> Maybe Int
times3 x =
  case x of
    Just num -> Just <| num * 3
    _ -> Nothing
    

times3' : Char -> Int -> Int
times3' key value =
  value * 3


a : Dict Char Int
a = Dict.insert 'a' 1 Dict.empty

b : Dict Char Int
b = Dict.update 'a' times3 a

c : Dict Char Int
c = Dict.insert 'b' 2 b

d : Dict Char Int
d = Dict.map times3' c

e : Dict Char Int
e = Dict.map (\key value -> value * 4) c

f = Dict.foldl (\key x acc -> acc + x) 0 e


main =
  div 
    []
    [ text ("a is: " ++ toString a)
    , br [] []
    , text ("b is: " ++ toString b)
    , br [] []
    , text ("c is: " ++ toString c)
    , br [] []
    , text ("d is: " ++ toString d)
    , br [] []
    , text ("e is: " ++ toString e)
    , br [] []
    , text ("f is: " ++ toString f)
    ]