def match(node)
      raise_unless_xpath!(node)
      pos = node.xpath("descendant::pos").first
      return nil if pos.nil?
      { matched: node.respond_to?(:name) ? node.name : "",
        line: pos["line"].to_i, column: pos["column"].to_i }
    end
def match(node)
      raise_unless_xpath!(node)
      pos = node.xpath("descendant::pos").first
      return nil if pos.nil?
      { matched: node.respond_to?(:name) ? node.name : "",
        line: pos["line"].to_i, column: pos["column"].to_i }
    end
Create a match from the specified node.