From 9a317e56f8a6126583f7d0c431bf878d9b1fe7b1 Mon Sep 17 00:00:00 2001
From: JSDurand <mmemmew@gmail.com>
Date: Sat, 8 Jul 2023 12:30:21 +0800
Subject: Finished the Emacs binding.

Now the binding part is finished.

What remains is a bug encountered when planting a fragment to the
forest which intersects a packed node, which would lead to invalid
forests.  This will also cause problem when planting a packed
fragment, but until now my testing grammars do not produce packed
fragments, so this problem is not encountered yet.

I am still figuring out efficient ways to solve this problem.
---
 chain/src/archive.txt | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

(limited to 'chain/src/archive.txt')

diff --git a/chain/src/archive.txt b/chain/src/archive.txt
index 030ccba..7bd6f31 100644
--- a/chain/src/archive.txt
+++ b/chain/src/archive.txt
@@ -493,3 +493,50 @@
 //         PaVi::Empty => Ok(self.root().ok_or(Error::IndexOutOfBounds(0, 0))?),
 //     }
 // }
+
+// /// Find the last child of the given node whose start and end
+// /// positions contain the given position.  If no such child is
+// /// found, return `Ok(None)`.
+// ///
+// /// The returned tuple is of the form (child, index), where
+// /// `child` is the index of the child node in question, and
+// /// `index` means that the child is the `index`-th child of the
+// /// node.
+// #[allow(dead_code)]
+// pub(crate) fn position_search(
+//     &self,
+//     node: usize,
+//     pos: usize,
+// ) -> Result<Option<(usize, usize)>, Error> {
+//     fn range_contains(label: GrammarLabel, pos: usize) -> bool {
+//         let start = label.start();
+// 
+//         if let Some(end) = label.end() {
+//             (start..end).contains(&pos)
+//         } else {
+//             (start..).contains(&pos)
+//         }
+//     }
+// 
+//     let node_label = self
+//         .vertex_label(node)?
+//         .ok_or(Error::NodeNoLabel(node))?
+//         .label();
+// 
+//     if !range_contains(node_label, pos) {
+//         return Ok(None);
+//     }
+// 
+//     for (index, child) in self.children_of(node)?.enumerate().rev() {
+//         let child_label = self
+//             .vertex_label(child)?
+//             .ok_or(Error::NodeNoLabel(child))?
+//             .label();
+// 
+//         if range_contains(child_label, pos) {
+//             return Ok(Some((child, index)));
+//         }
+//     }
+// 
+//     Ok(None)
+// }
-- 
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