Ticker.purs

ticker :: Aff _ Unit
ticker = do
  v1 <- makeEmptyVar
  _ <- forkAff $ forever $ delay (Milliseconds 1000.0) *> putVar unit v1

  v2 <- makeEmptyVar
  _ <- forkAff $ forever $ delay (Milliseconds 1000.0) *> putVar unit v2

  v3 <- liftAff makeEmptyVar

  let
      bounce = do
        var <- makeEmptyVar
        _ <- forkAff do
          v <- takeVar v1
          putVar v var
        takeVar var

      go = void $ forkAff $ forever do
        won <- sequential $ (Left <$> parallel bounce) <|> (Right <$> parallel (takeVar v2))
        putVar won v3

  void $ forkAff $ forever do
    v <- takeVar v3
    case v of
      Left _ -> liftEff $ log "left"
      Right _ -> liftEff $ log "right"

  go