node.cr

class Node
  include Enumerable

  property :left, :right, :data

  def initialize(data)
    @data = data
  end

  def each(&block)
    left.each(&block) if left
    block.call(self)
    right.each(&block) if right
  end

  def <=>(other)
    @data <=> other.data
  end
end