2 files changed, 104 insertions, 1 deletions
diff --git a/chain/src/archive.txt b/chain/src/archive.txt
index 79fe6d8..c93b4fe 100644
--- a/chain/src/archive.txt
+++ b/chain/src/archive.txt
@@ -638,3 +638,106 @@
 // }
 
 // Ok(())
+
+// let parents: Vec<_> = {
+//     if old_label.clone_index().is_some() {
+//         let mut parents = self.parents_of(node)?;
+//         assert_eq!(parents.len(), 1);
+//         node = parents.next().unwrap().node();
+//     }
+
+//     let parents: Vec<_> = self.parents_of(node)?.collect();
+
+//     let mut result: Vec<(Parent, usize)> = Vec::with_capacity(
+//         parents
+//             .iter()
+//             .map(|parent| {
+//                 self.parents_of(parent.node())
+//                     .map(|iter| iter.len())
+//                     .unwrap_or(0)
+//             })
+//             .sum(),
+//     );
+
+//     for parent in parents {
+//         let mut parent_label = self
+//             .vertex_label(parent.node())?
+//             .ok_or_else(|| Error::NodeNoLabel(parent.node()))?
+//             .label();
+
+//         assert!(get_rule_label(parent_label).is_some());
+
+//         if self.degree(parent.node())? != 1 {
+//             dbg!(parent);
+//             self.print_viz("dbg forest.gv").unwrap();
+
+//             panic!("assumption fails");
+//         }
+
+//         parent_label.set_end_option(end);
+
+//         let parent_label = ForestLabel::from(parent_label);
+
+//         let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+//         let new_parent = builder.add_vertex(parent_label);
+
+//         if let Some(packed) = new_packed {
+//             builder.add_edge(new_parent, packed, new_label)?;
+//         } else {
+//             builder.add_edge(new_parent, new_node, new_label)?;
+//         }
+
+//         result.extend(
+//             self.parents_of(parent.node())?
+//                 .map(|parent_parent| (parent_parent, new_parent)),
+//         );
+//     }
+
+//     result
+// };
+
+// for (parent, new_child) in parents {
+//     if !completingp {
+//         if self.has_same_children_until(
+//             parent.node(),
+//             parent.node(),
+//             parent.edge(),
+//             new_child,
+//         )? {
+//             continue;
+//         }
+
+//         // we don't add a child to parent.edge() here.
+//         let cloned = self.clone_node(parent.node(), parent.edge(), false)?;
+
+//         let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+//         builder.add_edge(cloned, new_child, new_label)?;
+//     } else {
+//         if self.has_same_children_except(
+//             parent.node(),
+//             parent.node(),
+//             parent.edge(),
+//             new_child,
+//         )? {
+//             continue;
+//         }
+
+//         // we don't add a child to parent.edge() here.
+//         let cloned = self.clone_node(parent.node(), parent.edge(), false)?;
+
+//         let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+//         builder.add_edge(cloned, new_child, new_label)?;
+
+//         let children_to_add: Vec<_> = builder
+//             .children_of(parent.node())?
+//             .skip(parent.edge() + 1)
+//             .collect();
+
+//         for child in children_to_add {
+//             builder.add_edge(cloned, child, new_label)?;
+//         }
+//     }
+// }
diff --git a/chain/src/item/default/mod.rs b/chain/src/item/default/mod.rs
index e0e2296..0dc613b 100644
--- a/chain/src/item/default/mod.rs
+++ b/chain/src/item/default/mod.rs
@@ -1596,7 +1596,7 @@ mod item_test {
 
         let atom = DefaultAtom::from_grammar(grammar)?;
 
-        // atom.print_nullables();
+        atom.print_nullables();
 
         let mut forest: DefaultForest<ForestLabel<GrammarLabel>> = DefaultForest::new_leaf_raw(
             ForestLabel::new(GrammarLabel::new(TNT::Non(0), 0), ForestLabelType::Plain),