# no explicit storage of information
# tree structure implicitly stores information
VoxelNode* = object
  case kind*: NodeKind
  of leaf:
    nil
  of node:
    children*: array[8, ref VoxelNode]

proc hash(x: VoxelNode): THash =
  var h: THash = 0
  case x.kind:
  of leaf:
    h = h !& 1
  of node:
    # hash each child node
    for idx in x.children:
      h = h !& hash(child)

  result = !$h


lib/system.nim(1825, 2) Error: parallel 'fields' iterator does not work for 'case' objects