Elm example for producing random values in a model

randomexample.elm

import Html exposing (div, button, text)
import Html.Events exposing (onClick)
import StartApp.Simple as StartApp
import Random exposing (Seed)

type alias Model = { seed : Seed, values : List Int }

initialModel : Model
initialModel =
  { seed = (Random.initialSeed 0), 
    values = [1, 2, 3]
  }

view address model =
  div []
    [ button [ onClick address AnotherOne ] [ text "Give me more randoms" ]
    , div [] [ text (toString model.values) ]
    ]

randomList : Seed -> (List Int, Seed)
randomList seed =
  let
    (numberOfItems, seed') = Random.generate (Random.int 0 30) seed
  in
    Random.generate (Random.list numberOfItems (Random.int 0 100)) seed'

type Action = AnotherOne

update : Action -> Model -> Model
update action model =
  case action of
    AnotherOne -> 
      let
        (randoms, newSeed) = randomList model.seed
      in
        { seed = newSeed, values = randoms }

main =
  StartApp.start { model = initialModel, view = view, update = update }