new startHEADmaster

Now I tested and discussed with claude, and had a working version of
this project.  The rest is to port the claude version to my own
writings.  So this serves as the starting point before that attempt.

In the new attempt the design is better, and a number of bugs were
found and supposedly fixed, so let us see how this goes at the end.

1 files changed, 81 insertions, 0 deletions

diff --git a/forest/src/archive_default.txt b/forest/src/archive_default.txt
index 5572ecc..d6e4e2e 100644
--- a/forest/src/archive_default.txt
+++ b/forest/src/archive_default.txt
@@ -523,3 +523,84 @@ mod forest_test {
         Ok(())
     }
 }
+
+// #[derive(Debug, Clone, Copy)]
+// enum Item<T: Copy + Clone + std::fmt::Debug> {
+//     Seen(T),
+//     Unseen(T),
+// }
+
+// use Item::*;
+
+// impl<T: Copy + Clone + std::fmt::Debug> Item<T> {
+//     fn is_seen(self) -> bool {
+//         matches!(self, Self::Seen(_))
+//     }
+
+//     fn value(&self) -> T {
+//         match self {
+//             Seen(v) => *v,
+//             Unseen(v) => *v,
+//         }
+//     }
+// }
+
+// let query_len = self.query.nodes_len();
+
+// let forest_len = forest.nodes_len();
+
+// let mut stack: Vec<(SkipState, usize)> = Vec::with_capacity(forest_len);
+
+// stack.push((SkipState::Any, root));
+
+// let mut query_stack: Vec<usize> = Vec::with_capacity(query_len);
+
+// query_stack.push(query_root);
+
+// let mut match_result = false;
+
+// 'search: while let Some(item) = stack.pop() {
+//     // if item.is_seen() {
+//     //     if match_result {
+//     //         continue;
+//     //     }
+
+//     //     // fallback
+//     // }
+
+//     let (state, top) = item;
+
+//     let qtop = if let Some(qtop) = query_stack.last() {
+//         *qtop
+//     } else {
+//         panic!("Query stack becomes empty");
+//     };
+
+//     let top_label = forest.vertex_label(top)?.ok_or(QRError::NodeNoLabel(top))?;
+
+//     // let top_status = top_label.status();
+
+//     if top_label.is_packed() {
+//         self.packs.push((top, 0));
+
+//         stack.try_reserve(forest.degree(top)?)?;
+
+//         stack.extend(forest.children_of(top)?.map(|child| (state, child)));
+
+//         continue 'search;
+//     }
+
+//     let query_label = self.query.label_of_vertex(qtop)?;
+
+//     if query_label.matches(top_label.label(), top_label.status()) {
+//         // Success branch
+
+//         match_result = true;
+
+//         // TODO: Deal with captures later
+//     } else {
+//         // Failure branch
+
+//         match_result = false;
+//     }
+// }