Info Need for path-dependent types blog post.

path-types-infoneed.scala

trait InfoNeed {
  type DataType
  /** Get the web request to fetch data */
  def request: WebRequest[DataType]
  /** Get the neighbors from some fetched data */
  def neighbors(data: DataType): Traversable[Node]
  /** Save the data to the data store. */
  def save(store: DataStore, data: DataType)
}