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.

1 files changed, 13 insertions, 49 deletions

diff --git a/chain/src/item/default/mod.rs b/chain/src/item/default/mod.rs
index 47e8c90..28bdbee 100644
--- a/chain/src/item/default/mod.rs
+++ b/chain/src/item/default/mod.rs
@@ -12,7 +12,7 @@ use graph_macro::Graph;
 
 use std::collections::HashSet;
 
-use core::fmt::Display;
+use std::fmt::Display;
 
 /// The type of errors for forest operations.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Ord, PartialOrd)]
@@ -216,6 +216,15 @@ impl<T: GraphLabel> Forest<T> for DefaultForest<ForestLabel<T>> {
             return Err(Error::IndexOutOfBounds(node_id, self.nodes_len()));
         }
 
+        // FIXME: We should take the presence of packed nodes into
+        // consideration.  That is, the fragment might have already
+        // been planted and packed, and we need to account for such
+        // possibilities.
+        //
+        // Moreover, the fragments might also contain packed nodes, in
+        // which case we need to check these multiple possibilities
+        // are properly contained.
+
         // We do a depth-first traversal to determine if every node
         // encountered has the same set of children (labels taken into
         // the consideration).
@@ -450,7 +459,7 @@ impl<T: GraphLabel> Forest<T> for DefaultForest<ForestLabel<T>> {
 
             // Make sure it only has one parent, which is the
             // representative node.
-            assert_eq!(parents.len(), 1);
+            // assert_eq!(parents.len(), 1);
 
             // We checked its length is 1, so it is safe to unwrap
             // here.
@@ -670,6 +679,8 @@ impl<T: GraphLabel> DefaultForest<ForestLabel<T>> {
 
 pub mod splone;
 
+pub mod extract;
+
 impl<T: GraphLabel> DefaultForest<T> {
     /// Create a forest with only one leaf from a raw label, unlike
     /// `new_leaf`, which transforms the label for convenience.
@@ -798,53 +809,6 @@ impl DefaultForest<ForestLabel<GrammarLabel>> {
         Ok(())
     }
 
-    /// 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)
-    }
-
     /// Set the position of every node.
     ///
     /// If ALLP is non-nil or if the node is a terminal node, also set