bug.elm

import Html exposing (..)
import Html.App as App
import Html.Attributes exposing (..)
import Html.Events exposing (onClick)
import Json.Decode as Json exposing ((:=))
import Mouse exposing (Position)

main =
  App.program
    { init = init
    , view = view
    , update = update
    , subscriptions = subscriptions
    }


-- MODEL


type alias Model =
    { state: Maybe (List Int)
    }
    
init : (Model, Cmd Msg)
init =
  ( { state = Nothing }, Cmd.none )

-- UPDATE


type Msg
    = Inc


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
  case msg of
    Inc ->
      case model.state of
        Just l ->
          let
            x = Maybe.withDefault 1 (Maybe.map (\i -> i+1) (List.head l))
            l = (x::l)
          in
            ( { model | state = Just l }, Cmd.none)
        Nothing ->
          ( { model | state = Just [1]}, Cmd.none)


-- SUBSCRIPTIONS


subscriptions : Model -> Sub Msg
subscriptions model =
  Sub.none


-- VIEW

view : Model -> Html Msg
view model =
  div []
    [ text (toString model.state)
    , button [onClick Inc] [text "yo"]
    ]