Port of https://github.com/evancz/elm-architecture-tutorial/tree/master/examples/1 to v 0.17 of Elm

Main.elm

import Html exposing (..)
import Html.Attributes exposing (style)
import Html.Events exposing (onClick)
import Html.App

type alias Model = Int

type Msg = Increment | Decrement

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

view : Model -> Html Msg
view model =
  div []
    [ button [ onClick Decrement ] [ text "-" ],
      div [ countStyle ] [ text (toString model) ],
      button [ onClick Increment ] [ text "+" ]
    ]

countStyle : Attribute msg
countStyle =
  style
    [ ("font-size", "20px"),
      ("font-family", "monospace"),
      ("display", "inline-block"),
      ("width", "50px"),
      ("text-align", "center")
    ]


main =
  Html.App.beginnerProgram
    { model = 0,
      update = update,
      view = view
    }