Elm simplification questions from Slack

breadcrumbs.elm

addBreadcrumb : Crumb -> List Crumb -> List Crumb
addBreadcrumb breadcrumb breadcrumbs =
    let
        cutBcrumbs bcrumbs newBcrumbs =
            case bcrumbs of
                Just crumbs ->
                    case List.head crumbs of
                        Just crumb ->
                            if breadcrumb /= crumb then
                                cutBcrumbs (List.tail crumbs) (List.append newBcrumbs [ crumb ])
                            else
                                List.append newBcrumbs [ crumb ]

                        Nothing ->
                            newBcrumbs

                Nothing ->
                    newBcrumbs
    in
        if List.any (\bc -> breadcrumb == bc) breadcrumbs then
            cutBcrumbs (Just breadcrumbs) []
        else
            List.append breadcrumbs [ breadcrumb ]

addBreadcrumb : Crumb -> List Crumb -> List Crumb
addBreadcrumb crumb crumbs =
    case crumbs of
        [] ->
            [ crumb ]

        x :: xs ->
            if x == crumb then
                [ crumb ]
            else
                x :: addBreadcrumb crumb xs

queryfn.elm

queryfn =
    let
        elementMaybe =
            Array.get index theQuery.selectlinescontainer

        element =
            case elementMaybe of
                Just el ->
                    el

                Nothing ->
                    xSelectLine

        newElement =
            { element | equation = input }

        newContainer =
            Array.set index newElement theQuery.selectlinescontainer

        newQueryEl =
            { theQuery | selectlinescontainer = newContainer }

        index =
            theQuery.queryId

        beforePart =
            if (index > 0) then
                List.take index model.queries
            else
                []

        afterPart =
            List.drop (index + 1) model.queries
    in
        { model | queries = beforePart ++ [ newQueryEl ] ++ afterPart } ! []

-- The first 7 lines, for example, could be this: `element = Array.get index theQuery.selectlinescontainer |> Maybe.withDefault xSelectLine`
-- The next few could be `newQueryEl = { theQuery | selectlinescontainer = Array.set theQuery.queryId { element | equation = input } theQuery.selectlinescontainer }`
-- and the next bit could be `queries = List.indexedMap (\idx -> if idx == theQuery.queryId then (always newQueryEl) else identity) model.queries`
-- now, with those in hand, you could look into spltting some of that off into helper functions, gradually moving your logic out of your `update` until it just dispatches functions, that call helpers to do their thing