Some random, useless Elm shit that I just want to show to people.

Main.elm

import Html exposing (Html, Attribute, text, program, section, div, button, input, label)
import Html.Events exposing (onClick)
import Html.Attributes exposing (class, type_, placeholder)

type alias Todo =
  { id : Int
  , description : String
  , done : Bool
  }
type alias Model = { todos : List Todo }

type Msg
  = Reset
  | AddTodo { id : Int, description : String }
  | RemoveTodo { id : Int }
  | CheckTodo { id : Int }

init : ( Model, Cmd msg )
init = ( { todos = [] }, Cmd.none )

update : Msg -> Model -> ( Model, Cmd msg )
update msg model =
  let newModel =
    case msg of
      Reset -> { todos = [] }
      AddTodo t -> { model | todos = { id = t.id, description = t.description, done = False } :: model.todos }
      RemoveTodo t -> { model | todos = List.filter (\e -> e.id == t.id) model.todos }
      CheckTodo t -> { model | todos = List.map (\e -> if e.id == t.id then { e | done = not e.done } else e) model.todos }
  in
  ( newModel, Cmd.none )

view : Model -> Html Msg
view model =
    section [ class "section" ]
        [ div [ class "field has-addons" ]
            [ div [ class "control is-expanded" ] [ input [ class "input", type_ "text", placeholder "Description" ] [] ]
            , div [ class "control" ] [ button [ class "button is-primary" ] [ text "Add Todo" ] ]
            ]
        ]

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

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