Simple Elm Counter

Counter.elm

import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)

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

--- MODEL

type alias Model = Int

model : Model
model =
  0

-- UPDATE

type Msg = Increment | Decrement | Reset

update : Msg -> Model -> Model
update msg model =
  case msg of
    Increment -> model + 1
    Decrement -> model - 1
    Reset -> 0

-- VIEW

view : Model -> Html Msg
view model =
  p []
    [ button [ onClick Decrement ] [ text "<" ]
    , span [] [ text (toString model) ]
    , button [ onClick Increment ] [ text ">" ]
    , button [ onClick Reset, disabled (model == 0) ] [ text "Reset" ]
    ]