1 files changed, 32 insertions, 3 deletions

diff --git a/chain/src/item/default/mod.rs b/chain/src/item/default/mod.rs
index 22069d2..3903162 100644
--- a/chain/src/item/default/mod.rs
+++ b/chain/src/item/default/mod.rs
@@ -628,7 +628,7 @@ impl<T: GraphLabel> DefaultForest<ForestLabel<T>> {
     /// case we clone it only when its degree is larger than one.
     ///
     /// Return either the original node or the cloned node at the end.
-    pub(crate) fn plant_if_needed(
+    pub(crate) fn plant_at_start(
         &mut self,
         node: usize,
         mut fragment: Self,
@@ -691,6 +691,34 @@ impl<T: GraphLabel> DefaultForest<ForestLabel<T>> {
 
         Ok(node)
     }
+
+    /// Extract the node from `pavi`.
+    ///
+    /// If pavi is a parent, this returns the child pointed to by the
+    /// represented edge.
+    ///
+    /// If pavi is a virtual node, this simply returns the virtual
+    /// node.
+    ///
+    /// If pavi is empty, this returns the root, unless the forest is
+    /// empty.
+    ///
+    /// # Guarantee
+    ///
+    /// The returned node is guaranteed to be a valid node.
+    pub(crate) fn node_from_pavi(&self, pavi: PaVi) -> Result<usize, Error> {
+        match pavi {
+            PaVi::Parent(node, edge) => Ok(self.nth_child(node, edge)?),
+            PaVi::Virtual(_, _, node) => {
+                if node >= self.nodes_len() {
+                    return Err(Error::IndexOutOfBounds(node, self.nodes_len()));
+                }
+
+                Ok(node)
+            }
+            PaVi::Empty => Ok(self.root().ok_or(Error::IndexOutOfBounds(0, 0))?),
+        }
+    }
 }
 
 pub mod splone;
@@ -831,6 +859,7 @@ impl DefaultForest<ForestLabel<GrammarLabel>> {
     /// `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,
@@ -1052,7 +1081,7 @@ impl DefaultForest<ForestLabel<GrammarLabel>> {
     // }
 
     /// Set the position of every node.
-    pub(crate) fn set_pos(&mut self, pos: usize) -> Result<(), Error> {
+    pub(crate) fn set_pos(&mut self, pos: usize, allp: bool) -> Result<(), Error> {
         let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
 
         for node in 0..builder.nodes_len() {
@@ -1064,7 +1093,7 @@ impl DefaultForest<ForestLabel<GrammarLabel>> {
 
             label_label.set_start(pos);
 
-            if matches!(label_label.label().tnt(), Some(TNT::Ter(_))) {
+            if allp || matches!(label_label.label().tnt(), Some(TNT::Ter(_))) {
                 label_label.set_end(pos + 1);
             } else if builder.degree(node)? == 1 && label_label.label().rule().is_some() {
                 let child = builder.children_of(node)?.next().unwrap();