わーい、すごーい

import Html exposing (Html, text)


main =
  Html.beginnerProgram { model = model, view = view, update = update }


type alias Model = String


model : Model
model =
  ""
    |> update Wai
    |> update Sugoi
    |> update Tanoshii
    |> update (Friends "クソリプ")


type Msg
    = Wai
    | Sugoi
    | Tanoshii
    | Friends String


update : Msg -> Model -> Model
update msg model =
  case msg of
    Wai ->
        model ++ "わーい"

    Sugoi ->
        model ++ "すごーい"

    Tanoshii ->
        model ++ "たのしー"

    Friends skill ->
        model ++ "君は" ++ skill ++ "がとくいな、フレンズなんだね!!"


view : Model -> Html Msg
view model = text model

Try Elm

元ネタ
http://qiita.com/t_ishida/items/bae7e62950d81f427f13