EventLog.elm

module EventLog where

import Html            exposing (..)
import Html.Events     exposing (..)
import Html.Attributes exposing (..)
import Signal          exposing (..)
import StartApp.Simple exposing (..)

type alias Model =
  { events: List String }

initialModel : Model
initialModel =
  { events = [] }

type Action = Mark String
            | Reset

update : Action -> Model -> Model
update action log =
  case action of
    Mark date ->
      { log | events <- log.events ++ [date] }
    Reset ->
      { log | events <- [] }

view : Address Action -> Model -> Html
view address model =
  div []
    [ button [ onClick address (Mark "?") ] [ text "Mark" ],
      button [ onClick address Reset ] [ text "Reset" ],
      h2 [] [ text (model.events |> List.length |> toString), text " Events" ],
      div [] (List.map (\t -> text t) model.events)
    ]

main : Signal Html
main =
  StartApp.Simple.start
    { model = initialModel,
      view = view,
      update = update }

@kouphax thanks for your nice post!

It seems that StartApp.Simple is now needed instead of StartApp, so here's the updated code ^^ :)