title: Hierarchical navigation w/ Scala in the Play! framework
body: <p>I need to implement a hierarchy of categories (basically a tree structure). As I am new to Scala, I suspect there is a very good functional approach to this problem.</p>
  
  <p>I have used nested sets in PHP/mysql before. Is there an easy way to create a tree structure that enables me to easily retrieve parent and child nodes from the tree, starting out from a database table that consists of</p>
  
  <p>id
  parent_id
  label</p>
  
  <p>?</p>
  
  <p>My feeling is that this is where Scala should shine with its functional flavour.</p>