class GParserNode #Tree node for GParser
  def initialize(parent = nil)
    @children = Array.new
    @parent.attach_child(self) unless parent == nil
  end

  def attach_child(child)
    @children.push child
    child.parent = self
  end

  def detach_child_by_index(index)
    @children[index].parent = nil
    @children.delete(index)
  end

  def child_index(child)
    index = 0
    @children.each do |_child|
      return index if _child == child
      index += 1
    end
  end

  attr_accessor :parent, :children, :data
end