Dict/Set.fold*ByOrder proposal

[pravdomil]

Hi, I was searching for function that gets things from Dict/Set by prefix (for indexing purposes).
So I found that fold*WithOrder function would be quite handy.

foldlByOrder : (k -> Order) -> (k -> v -> a -> a) -> a -> Dict k v -> a
foldlByOrder toOrder fn acc a =
    case a of
        RBEmpty_elm_builtin ->
            acc

        RBNode_elm_builtin _ k v left right ->
            case toOrder k of
                LT ->
                    foldlByOrder toOrder fn acc left

                EQ ->
                    foldlByOrder toOrder fn (fn k v (foldlByOrder toOrder fn acc left)) right

                GT ->
                    foldlByOrder toOrder fn acc right

[github-actions]

Thanks for reporting this! To set expectations:

• Issues are reviewed in batches, so it can take some time to get a response.
• Ask questions a community forum. You will get an answer quicker that way!
• If you experience something similar, open a new issue. We like duplicates.

Finally, please be patient with the core team. They are trying their best with limited resources.