recovered tooltip from 6e77ddb1e3fb: non-null default is required as prerequisite;
/*  Title:      Tools/Graphview/mutator.scala
    Author:     Markus Kaiser, TU Muenchen
    Author:     Makarius
Filters and add-operations on graphs.
*/
package isabelle.graphview
import isabelle._
import java.awt.Color
import scala.collection.immutable.SortedSet
object Mutator
{
  sealed case class Info(enabled: Boolean, color: Color, mutator: Mutator)
  def make(visualizer: Visualizer, m: Mutator): Info =
    Info(true, visualizer.Colors.next, m)
  class Graph_Filter(
    val name: String,
    val description: String,
    pred: Model.Graph => Model.Graph) extends Filter
  {
    def filter(graph: Model.Graph) : Model.Graph = pred(graph)
  }
  class Graph_Mutator(
    val name: String,
    val description: String,
    pred: (Model.Graph, Model.Graph) => Model.Graph) extends Mutator
  {
    def mutate(complete_graph: Model.Graph, graph: Model.Graph): Model.Graph =
      pred(complete_graph, graph)
  }
  class Node_Filter(
    name: String,
    description: String,
    pred: (Model.Graph, String) => Boolean)
    extends Graph_Filter(name, description, g => g.restrict(pred(g, _)))
  class Edge_Filter(
    name: String,
    description: String,
    pred: (Model.Graph, String, String) => Boolean)
    extends Graph_Filter(
      name,
      description,
      g => (g /: g.dest) {
        case (graph, ((from, _), tos)) =>
          (graph /: tos)((gr, to) =>
            if (pred(gr, from, to)) gr else gr.del_edge(from, to))
      })
  class Node_Family_Filter(
    name: String,
    description: String,
    reverse: Boolean,
    parents: Boolean,
    children: Boolean,
    pred: (Model.Graph, String) => Boolean)
    extends Node_Filter(
      name,
      description,
      (g, k) =>
        reverse !=
          (pred(g, k) ||
            (parents && g.all_preds(List(k)).exists(pred(g, _))) ||
            (children && g.all_succs(List(k)).exists(pred(g, _)))))
  case class Identity()
    extends Graph_Filter(
      "Identity",
      "Does not change the graph.",
      g => g)
  case class Node_Expression(
    regex: String,
    reverse: Boolean,
    parents: Boolean,
    children: Boolean)
    extends Node_Family_Filter(
      "Filter by Name",
      "Only shows or hides all nodes with any family member's name matching a regex.",
      reverse,
      parents,
      children,
      (g, k) => (regex.r findFirstIn k).isDefined)
  case class Node_List(
    list: List[String],
    reverse: Boolean,
    parents: Boolean,
    children: Boolean)
    extends Node_Family_Filter(
      "Filter by Name List",
      "Only shows or hides all nodes with any family member's name matching any string in a comma separated list.",
      reverse,
      parents,
      children,
      (g, k) => list.exists(_ == k))
  case class Edge_Endpoints(source: String, dest: String)
    extends Edge_Filter(
      "Hide edge",
      "Hides the edge whose endpoints match strings.",
      (g, s, d) => !(s == source && d == dest))
  private def add_node_group(from: Model.Graph, to: Model.Graph, keys: List[String]) =
  {
    // Add Nodes
    val with_nodes =
      (to /: keys)((graph, key) => graph.default_node(key, from.get_node(key)))
    // Add Edges
    (with_nodes /: keys) {
      (gv, key) => {
        def add_edges(g: Model.Graph, keys: SortedSet[String], succs: Boolean) =
          (g /: keys) {
            (graph, end) => {
              if (!graph.keys_iterator.contains(end)) graph
              else {
                if (succs) graph.add_edge(key, end)
                else graph.add_edge(end, key)
              }
            }
          }
        add_edges(
          add_edges(gv, from.imm_preds(key), false),
          from.imm_succs(key), true)
      }
    }
  }
  case class Add_Node_Expression(regex: String)
    extends Graph_Mutator(
      "Add by name",
      "Adds every node whose name matches the regex. " +
      "Adds all relevant edges.",
      (complete_graph, graph) =>
        add_node_group(complete_graph, graph,
          complete_graph.keys.filter(k => (regex.r findFirstIn k).isDefined).toList))
  case class Add_Transitive_Closure(parents: Boolean, children: Boolean)
    extends Graph_Mutator(
      "Add transitive closure",
      "Adds all family members of all current nodes.",
      (complete_graph, graph) => {
        val withparents =
          if (parents) add_node_group(complete_graph, graph, complete_graph.all_preds(graph.keys))
          else graph
        if (children)
          add_node_group(complete_graph, withparents, complete_graph.all_succs(graph.keys))
        else withparents
      })
}
trait Mutator
{
  val name: String
  val description: String
  def mutate(complete_graph: Model.Graph, graph: Model.Graph): Model.Graph
  override def toString: String = name
}
trait Filter extends Mutator
{
  def mutate(complete_graph: Model.Graph, graph: Model.Graph) = filter(graph)
  def filter(graph: Model.Graph) : Model.Graph
}