class Prism::DotVisitor

def visit_undef_node(node)

Visit a UndefNode node. 
def visit_undef_node(node)
  table = Table.new("UndefNode")
  id = node_id(node)
  # names
  if node.names.any?
    table.field("names", port: true)
    waypoint = "#{id}_names"
    digraph.waypoint("#{waypoint};")
    digraph.edge("#{id}:names -> #{waypoint};")
    node.names.each { |child| digraph.edge("#{waypoint} -> #{node_id(child)};") }
  else
    table.field("names", "[]")
  end
  # keyword_loc
  table.field("keyword_loc", location_inspect(node.keyword_loc))
  digraph.nodes << <<~DOT
    #{id} [
      label=<#{table.to_dot.gsub(/\n/, "\n  ")}>
    ];
  DOT
  super
end