sclass HuffmanTree {
  settable Node root;
  
  /*
  algebraic Node {
    constructor Branch {
      settable Node zero;
      settable Node one;
    }
    constructor Leaf {
      settable byte literal;
    }
  }
  */
  
  abstract static class Node {}
  
  static class Branch > Node {
    settable Node zero;
    settable Node one;
  }
  
  static class Leaf > Node {
    settable byte literal;
  }
}