Dispatcher function for elm update functions.

Update.elm

module Update exposing (dispatch)

{-| Create update function

    updater1 : Msg -> Model -> Maybe Model
    updater1 msg model =
        case msg of
            Foo ->
                Just { model | foo = "Foo" }
            _ ->
                Nothing
       
    updater2 : Msg -> Model -> Maybe Model
    updater2 msg model =
        case msg of
            Bar ->
                Just { model | bar = "Bar" }
            _ ->
                Nothing
    
    updaters : List (Msg -> Model -> Maybe Model)
    updaters =
        [ updater1
        , updater2
        ]
    
    main : Program Never Model Msg
    main =
        Html.beginnerProgram
            { model = init
            , view = view
            , update = dispatch updaters msg model
            }
-}
dispatch : List (msg -> model -> Maybe model) -> msg -> model -> model
dispatch updaters msg model =
    case updaters of
        [] ->
            model

        f :: fs ->
            case f msg model of
                Just model ->
                    model

                Nothing ->
                    dispatch fs msg model