Test.elm

module Test exposing (..)

{-| A binary search tree will often look roughly like this.
Every node will either be the `Empty` node, or a node with
a key, a value and left and right children. In this case, we
also have an extra `Int` to keep track of the height, but
that's not relevant to the example at hand.
-}
type Dict k v
    = Empty
    | Node Int k v (Dict k v) (Dict k v)


foldl : (k -> v -> a -> a) -> a -> Dict k v -> a
foldl op acc dict =
    case dict of
        Empty ->
            acc

        Node _ key val left right ->
            foldl op acc left
                |> op key val
                |> (\acc -> foldl op acc right)