+
+ public boolean isTransparent() { return hp.size()==1; }
+ public boolean isHidden() { return hp.size()==0; }
+ public void edges(GraphViz.Node n) { for(Forest f : hp) f.edges(n); }
+ public GraphViz.Node toGraphViz(GraphViz gv) {
+ if (hp.size()==0) return null;
+ if (hp.size()==1) return hp.iterator().next().toGraphViz(gv);
+ if (gv.hasNode(this)) return gv.createNode(this);
+ GraphViz.Node n = gv.createNode(this);
+ n.label = "?";
+ n.color = "red";
+ for(Forest f : hp) n.edge(f);
+ return n;
+ }
+