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-rw-r--r--chain/src/item/default/mod.rs810
-rw-r--r--chain/src/item/default/splone.rs760
2 files changed, 1570 insertions, 0 deletions
diff --git a/chain/src/item/default/mod.rs b/chain/src/item/default/mod.rs
new file mode 100644
index 0000000..7ecc70d
--- /dev/null
+++ b/chain/src/item/default/mod.rs
@@ -0,0 +1,810 @@
+//! This module provides a default implementation of iten derivation
+//! forest.
+
+use super::*;
+use crate::atom::default::DefaultAtom;
+use grammar::{GrammarLabel, GrammarLabelType};
+use graph::{
+ builder::BuilderMut, labelled::binary::PLGBuilderMut, Graph, LabelGraph, PLGraph, RedirectGraph,
+};
+
+use core::fmt::Display;
+
+/// The type of errors for forest operations.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Ord, PartialOrd)]
+pub enum Error {
+ /// An index is out of bounds.
+ ///
+ /// The first component is the index that is out of bounds, and
+ /// the second component is the current length of nodes.
+ IndexOutOfBounds(usize, usize),
+ /// The forest does not permit duplicate nodes but encounters a
+ /// repeated node.
+ DuplicatedNode(usize),
+ /// A node has no labels while it is required to have one.
+ NodeNoLabel(usize),
+ /// Encounter an invalid error in converting from an error of
+ /// graphs.
+ InvalidGraphError(GError),
+ /// Encounter an error when converting forest labels.
+ LabelConversion(ForestLabelError),
+ /// Trying to split a packed node.
+ SplitPack(usize),
+}
+
+impl Display for Error {
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ match self {
+ Error::IndexOutOfBounds(index, bound) => {
+ write!(f, "index {index} is out of bound {bound}")
+ }
+ Error::DuplicatedNode(n) => write!(f, "node {n} is duplicated"),
+ Error::InvalidGraphError(ge) => write!(f, "invalid error: {ge}"),
+ Error::NodeNoLabel(n) => write!(f, "node {n} has no labels, but it should have one"),
+ Error::LabelConversion(le) => write!(f, "fail to convert labels: {le}"),
+ Error::SplitPack(n) => write!(f, "cannot split the packed node {n}"),
+ }
+ }
+}
+
+impl std::error::Error for Error {}
+
+impl From<GError> for Error {
+ fn from(ge: GError) -> Self {
+ match ge {
+ GError::IndexOutOfBounds(index, bound) => Self::IndexOutOfBounds(index, bound),
+ GError::DuplicatedNode(n) => Self::DuplicatedNode(n),
+ _ => Self::InvalidGraphError(ge),
+ }
+ }
+}
+
+impl From<ForestLabelError> for Error {
+ fn from(le: ForestLabelError) -> Self {
+ Self::LabelConversion(le)
+ }
+}
+
+/// A default implementation of forest.
+#[derive(Debug, Clone)]
+pub struct DefaultForest<T: GraphLabel> {
+ graph: PLGraph<T>,
+ root: Option<usize>,
+}
+
+impl<T: GraphLabel> Default for DefaultForest<T> {
+ fn default() -> Self {
+ let graph = Default::default();
+ let root = None;
+
+ Self { graph, root }
+ }
+}
+
+impl<T: GraphLabel> AsRef<DefaultForest<T>> for DefaultForest<T> {
+ fn as_ref(&self) -> &DefaultForest<T> {
+ self
+ }
+}
+
+impl<T: GraphLabel> Graph for DefaultForest<T> {
+ type Iter<'a> = <PLGraph<T> as Graph>::Iter<'a>
+ where
+ Self: 'a;
+
+ #[inline]
+ fn is_empty(&self) -> bool {
+ self.graph.is_empty()
+ }
+
+ #[inline]
+ fn nodes_len(&self) -> usize {
+ self.graph.nodes_len()
+ }
+
+ #[inline]
+ fn edges_len(&self) -> Option<usize> {
+ self.graph.edges_len()
+ }
+
+ #[inline]
+ fn children_of(&self, node_id: usize) -> Result<Self::Iter<'_>, GError> {
+ self.graph.children_of(node_id)
+ }
+
+ #[inline]
+ fn degree(&self, node_id: usize) -> Result<usize, GError> {
+ self.graph.degree(node_id)
+ }
+
+ #[inline]
+ fn is_empty_node(&self, node_id: usize) -> Result<bool, GError> {
+ self.graph.is_empty_node(node_id)
+ }
+
+ #[inline]
+ fn has_edge(&self, source: usize, target: usize) -> Result<bool, GError> {
+ self.graph.has_edge(source, target)
+ }
+
+ fn replace_by_builder(&mut self, _builder: impl graph::Builder<Result = Self>) {
+ unimplemented!()
+ }
+
+ #[inline]
+ fn print_viz(&self, filename: &str) -> Result<(), std::io::Error> {
+ self.graph.print_viz(filename)
+ }
+}
+
+impl<T: GraphLabel> ParentsGraph for DefaultForest<T> {
+ type Iter<'a>= <PLGraph<T> as ParentsGraph>::Iter<'a>
+ where
+ Self:'a;
+
+ #[inline]
+ fn parents_of(&self, node_id: usize) -> Result<<Self as ParentsGraph>::Iter<'_>, GError> {
+ self.graph.parents_of(node_id)
+ }
+
+ #[inline]
+ fn nth_child(&self, node_id: usize, n: usize) -> Result<usize, GError> {
+ self.graph.nth_child(node_id, n)
+ }
+
+ #[inline]
+ fn edge_to_parent(
+ &self,
+ source: usize,
+ target: usize,
+ ) -> Result<Option<graph::Parent>, GError> {
+ self.graph.edge_to_parent(source, target)
+ }
+}
+
+impl<T: GraphLabel> LabelGraph<T> for DefaultForest<T> {
+ type Iter<'a> = std::iter::Empty<usize>
+ where
+ Self: 'a;
+
+ type LabelIter<'a> = std::iter::Empty<(&'a T, <Self as LabelGraph<T>>::Iter<'a>)>
+ where
+ Self: 'a,
+ T: 'a;
+
+ type EdgeLabelIter<'a> = std::iter::Empty<T>
+ where
+ Self: 'a,
+ T: 'a;
+
+ #[inline]
+ fn query_label(&self, label: T) -> Option<usize> {
+ self.graph.query_label(label)
+ }
+
+ #[inline]
+ fn vertex_label(&self, node_id: usize) -> Result<Option<T>, GError> {
+ self.graph.vertex_label(node_id)
+ }
+
+ fn edge_label(
+ &self,
+ _source: usize,
+ _target: usize,
+ ) -> Result<Self::EdgeLabelIter<'_>, GError> {
+ unimplemented!("edges have no labels")
+ }
+
+ fn find_children_with_label(
+ &self,
+ _node_id: usize,
+ _label: &T,
+ ) -> Result<<Self as LabelGraph<T>>::Iter<'_>, GError> {
+ unimplemented!("edges have no labels")
+ }
+
+ fn labels_of(&self, _node_id: usize) -> Result<Self::LabelIter<'_>, GError> {
+ unimplemented!("edges have no labels")
+ }
+
+ fn has_edge_label(&self, _node_id: usize, _label: &T, _target: usize) -> Result<bool, GError> {
+ unimplemented!("edges have no labels")
+ }
+}
+
+impl<T: GraphLabel> Forest<T> for DefaultForest<ForestLabel<T>> {
+ type Error = Error;
+
+ fn root(&self) -> Option<usize> {
+ self.root
+ }
+
+ fn new_leaf(label: T) -> Self {
+ let mut graph = PLGraph::default();
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut graph);
+
+ let root = Some(builder.add_vertex(ForestLabel::from(label)));
+
+ Self { graph, root }
+ }
+
+ fn transform_label(
+ &mut self,
+ node_id: usize,
+ transform: impl FnOnce(T) -> T,
+ ) -> Result<(), Self::Error> {
+ let vertex_label = self
+ .vertex_label(node_id)?
+ .ok_or(Error::NodeNoLabel(node_id))?;
+
+ let transformed_label = transform(vertex_label.label());
+
+ let transformed_label = ForestLabel::new(transformed_label, vertex_label.status);
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ builder
+ .set_label(node_id, transformed_label)
+ .map_err(Into::into)
+ }
+
+ fn is_prefix<F>(&self, node_id: usize, fragment: F) -> Result<bool, Self::Error>
+ where
+ F: Borrow<Self>,
+ {
+ if !self.has_node(node_id) {
+ return Err(Error::IndexOutOfBounds(node_id, self.nodes_len()));
+ }
+
+ // We do a depth-first traversal to determine if every node
+ // encountered has the same set of children (labels taken into
+ // the consideration).
+
+ let fragment = fragment.borrow();
+
+ let mut frag_stack = Vec::with_capacity(fragment.nodes_len());
+
+ let mut self_stack = Vec::with_capacity(fragment.nodes_len());
+
+ let frag_root = if let Some(root) = fragment.root() {
+ root
+ } else {
+ // an empty forest is a prefix of any forest.
+ return Ok(true);
+ };
+
+ frag_stack.push(frag_root);
+ self_stack.push(node_id);
+
+ // defer popping
+ while let (Some(frag_top), Some(self_top)) =
+ (frag_stack.last().copied(), self_stack.last().copied())
+ {
+ frag_stack.pop();
+ self_stack.pop();
+
+ if fragment.vertex_label(frag_top)? != self.vertex_label(self_top)? {
+ // not a prefix
+ return Ok(false);
+ }
+
+ let mut self_children = self.children_of(self_top)?;
+
+ for child in fragment.children_of(frag_top)? {
+ if let Some(self_child) = self_children.next() {
+ frag_stack.push(child);
+ self_stack.push(self_child);
+ } else {
+ // too few children
+ return Ok(false);
+ }
+ }
+ }
+
+ // Check both stacks are empty at the end.
+ Ok(frag_stack.is_empty() && self_stack.is_empty())
+ }
+
+ fn plant<F>(&mut self, node_id: usize, fragment: F, planted: bool) -> Result<(), Self::Error>
+ where
+ F: Borrow<Self>,
+ {
+ // Convert self to a builder_mut, and traverse fragment in a
+ // depth-first manner and adjoin corresponding nodes along the
+ // way.
+
+ if !self.has_node(node_id) {
+ return Err(Error::IndexOutOfBounds(node_id, self.nodes_len()));
+ }
+
+ let fragment = fragment.borrow();
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ let root = if let Some(root) = fragment.root() {
+ root
+ } else {
+ // Nothing to do to plant an empty forest.
+ return Ok(());
+ };
+
+ // Just a dummy label for use in adding edges.
+ //
+ // REVIEW: I probably should refactor the API for builder_mut.
+ let root_label = fragment
+ .vertex_label(root)?
+ .ok_or(Error::NodeNoLabel(root))?;
+
+ let nodes_len = fragment.nodes_len();
+
+ /// If the fragment root has a duplicate label, the forest
+ /// will not grow, so we use the label to find the adjoined
+ /// node index.
+ ///
+ /// The nodes hava already been added to the forest, so it is
+ /// safe to call unwrap.
+ macro_rules! conversion (
+ ($node:expr) => {
+ {
+ builder
+ .query_label(
+ fragment
+ .vertex_label($node)?
+ .ok_or(Error::NodeNoLabel($node))?
+ ).unwrap()
+ }
+ }
+ );
+
+ // If the fragment has been planted before, we just add an
+ // edge.
+
+ if planted {
+ builder.add_edge(node_id, conversion!(root), root_label)?;
+
+ return Ok(());
+ }
+
+ // First adjoin those nodes and join the edges later.
+
+ for node in 0..nodes_len {
+ let label = fragment
+ .vertex_label(node)?
+ .ok_or(Error::NodeNoLabel(node))?;
+
+ builder.add_vertex(label);
+ }
+
+ // Don't forget to join the new sub-forest to the original
+ // forest, at the specified position.
+
+ builder.add_edge(node_id, conversion!(root), root_label)?;
+
+ // We can try to calculate the depth of fragments, if we need
+ // to lower the memory usage. But in our use cases, we
+ // usually deal with fragments where each node has at most one
+ // child, so the depth is supposed to be equal to the length
+ // in this case.
+ let mut stack = Vec::with_capacity(fragment.nodes_len());
+
+ stack.push(root);
+
+ let mut seen_nodes = std::collections::HashSet::<usize>::new();
+
+ while let Some(top) = stack.pop() {
+ seen_nodes.insert(top);
+
+ for child in fragment.children_of(top)? {
+ builder.add_edge(conversion!(top), conversion!(child), root_label)?;
+
+ if !seen_nodes.contains(&child) {
+ seen_nodes.insert(child);
+ stack.push(child);
+ }
+ }
+ }
+
+ Ok(())
+ }
+
+ fn clone_node(
+ &mut self,
+ node_id: usize,
+ preserved_edges_num: usize,
+ no_new_clone: bool,
+ ) -> Result<usize, Self::Error> {
+ let builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ let old_label = builder
+ .vertex_label(node_id)?
+ .ok_or(Error::NodeNoLabel(node_id))?;
+
+ if old_label.is_packed() {
+ dbg!(node_id, old_label);
+ return Err(ForestLabelError::ClonePack.into());
+ }
+
+ // We are sure old_label is not packed here, so it is safe to
+ // unwrap.
+ let new_label = old_label
+ .clone::<DefaultForest<ForestLabel<T>>>(self.borrow())
+ .unwrap();
+
+ if old_label.clone_index().is_some() {
+ if no_new_clone {
+ return Ok(new_label.clone_index().unwrap());
+ }
+
+ let mut parents = self.parents_of(node_id)?;
+
+ // Make sure it only has one parent, which is the
+ // representative node.
+ assert_eq!(parents.len(), 1);
+
+ // We checked its length is 1, so it is safe to unwrap
+ // here.
+ let rep_node = parents.next().unwrap().node();
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ let new_clone = builder.add_vertex(new_label);
+
+ builder.add_edge(rep_node, new_clone, new_label)?;
+
+ let preserve_children: Vec<_> = builder
+ .children_of(node_id)?
+ .take(preserved_edges_num)
+ .collect();
+
+ for child in preserve_children.into_iter() {
+ builder.add_edge(new_clone, child, new_label)?;
+ }
+
+ return Ok(new_clone);
+ }
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ // We are sure old_label is not a clone here, so it is safe to
+ // unwrap.
+ let rep_label = old_label.pack().unwrap();
+
+ // Make a new node
+ let new_index = builder.add_vertex(rep_label);
+
+ // Re-direct parents to the new node.
+ //
+ // This must be done before pointing the new node to the old
+ // node, otherwise that edge will be redirected as well.
+
+ // Unfortunately I cannot loop through parents and mutate them
+ // at the same time, so I first collect them into a vector.
+ let parents: Vec<_> = builder.parents_of(node_id)?.collect();
+
+ for parent in parents.into_iter() {
+ builder.redirect(parent.node(), parent.edge(), new_index)?;
+ }
+
+ // Point the new node to the old node. OLD_LABEL is just a
+ // place holder.
+
+ builder.add_edge(new_index, node_id, old_label)?;
+
+ // Modify the label of the old node.
+
+ builder.set_label(node_id, new_label)?;
+
+ // Make another clone
+
+ // new_label is cloned, so is guaranteed not to be packed, and
+ // we are safe to unwrap.
+ let new_label = new_label
+ .clone::<DefaultForest<ForestLabel<T>>>(self.borrow())
+ .unwrap();
+
+ if no_new_clone {
+ return Ok(new_label.clone_index().unwrap());
+ }
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ let new_clone = builder.add_vertex(new_label);
+
+ builder.add_edge(new_index, new_clone, new_label)?;
+
+ let preserve_children: Vec<_> = builder
+ .children_of(node_id)?
+ .take(preserved_edges_num)
+ .collect();
+
+ for child in preserve_children {
+ builder.add_edge(new_clone, child, new_label)?;
+ }
+
+ Ok(new_clone)
+ }
+}
+
+impl<T: GraphLabel> PartialEq for DefaultForest<ForestLabel<T>> {
+ fn eq(&self, other: &Self) -> bool {
+ let self_root = self.root();
+ let other_root = other.root();
+
+ if (self_root.is_some() && other_root.is_none())
+ || (self_root.is_none() && other_root.is_some())
+ {
+ return false;
+ } else if self_root.is_none() && other_root.is_none() {
+ return true;
+ }
+
+ // both roots are not empty
+
+ let self_root = self_root.unwrap();
+ let other_root = other_root.unwrap();
+
+ self.is_prefix(self_root, other).unwrap_or(false)
+ && other.is_prefix(other_root, self).unwrap_or(false)
+ }
+}
+
+pub mod splone;
+
+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.
+ pub fn new_leaf_raw(label: T) -> Self {
+ let mut graph = PLGraph::default();
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut graph);
+
+ let root = Some(builder.add_vertex(label));
+
+ Self { graph, root }
+ }
+}
+
+impl<T: GraphLabel> Eq for DefaultForest<ForestLabel<T>> {}
+
+impl DefaultForest<ForestLabel<GrammarLabel>> {
+ /// Prints the forest without nodes that do not have ending
+ /// positions.
+ ///
+ /// Nodes without ending positions are "unclosed nodes" that only
+ /// serve the role of creating nodes with ending positions.
+ pub fn print_closed_viz(&self, filename: &str) -> Result<(), std::io::Error> {
+ let discard_nodes: std::collections::HashSet<_> = self
+ .nodes()
+ .filter(|node| match self.vertex_label(*node) {
+ Ok(label) => {
+ if let Some(label) = label {
+ label.label().end().is_none()
+ } else {
+ true
+ }
+ }
+ Err(_) => true,
+ })
+ .collect();
+
+ let filename = format!("output/{filename}");
+
+ let preamble = "digraph nfa {
+ fontname=\"Helvetica,Arial,sans-serif\"
+ node [fontname=\"Helvetica,Arial,sans-serif\"]
+ edge [fontname=\"Helvetica,Arial,sans-serif\"]
+ rankdir=LR;\n";
+
+ let mut post = String::new();
+
+ for node in self.nodes() {
+ if discard_nodes.contains(&node) {
+ continue;
+ }
+
+ post.push_str(&format!(
+ " {node} [label = \"{}\"]\n",
+ match self.vertex_label(node) {
+ Ok(Some(label)) => {
+ format!("{label}")
+ }
+ _ => {
+ " ε ".to_owned()
+ }
+ }
+ ));
+ }
+
+ for (source, target) in self.edges() {
+ if discard_nodes.contains(&source) || discard_nodes.contains(&target) {
+ continue;
+ }
+
+ post.push_str(&format!(" {source} -> {target}\n"));
+ }
+
+ post.push_str("}\n");
+
+ let result = format!("{preamble}{post}");
+
+ if std::fs::metadata(&filename).is_ok() {
+ std::fs::remove_file(&filename)?;
+ }
+
+ let mut file = std::fs::File::options()
+ .write(true)
+ .create(true)
+ .open(&filename)?;
+
+ use std::io::Write;
+
+ file.write_all(result.as_bytes())
+ }
+}
+
+/// Print the labels found in the forest, so that we can easily
+/// understand what those labels mean.
+pub fn print_labels(
+ atom: impl Borrow<DefaultAtom>,
+ forest: impl Borrow<DefaultForest<ForestLabel<GrammarLabel>>>,
+) -> Result<(), Box<dyn std::error::Error>> {
+ let forest = forest.borrow();
+ let atom = atom.borrow();
+
+ for node in forest.nodes() {
+ let label = forest.vertex_label(node)?;
+
+ if let Some(label) = label {
+ let label = label.label.label();
+
+ match label {
+ GrammarLabelType::TNT(tnt) => {
+ println!("{tnt} = {}", atom.name_of_tnt(tnt)?);
+ }
+ GrammarLabelType::Rule(pos) => {
+ println!("pos {pos} = {}", atom.rule_pos_string(pos)?);
+ }
+ }
+ } else {
+ return Err(Error::NodeNoLabel(node).into());
+ }
+ }
+
+ Ok(())
+}
+
+#[allow(unused_macros)]
+macro_rules! leaf (
+ ($label:expr, $type:tt) =>{
+ DefaultForest::<ForestLabel<$type>>::new_leaf($label)
+ };
+ ($label:expr) => {
+ DefaultForest::<ForestLabel<usize>>::new_leaf($label)
+ }
+);
+
+#[allow(unused_imports)]
+pub(crate) use leaf;
+
+#[cfg(test)]
+mod item_test {
+ use super::*;
+
+ #[test]
+ fn test_forest_api() -> Result<(), Box<dyn std::error::Error>> {
+ let forest: DefaultForest<ForestLabel<usize>> = Default::default();
+
+ // empty forest
+
+ assert!(forest.is_empty());
+
+ // leaf forest
+
+ let mut forest = leaf!(0, usize);
+
+ assert_eq!(forest.nodes_len(), 1);
+ assert_eq!(forest.root(), Some(0));
+
+ // add some child
+
+ forest.plant(0, leaf!(1), false)?;
+
+ assert_eq!(forest.nodes_len(), 2);
+ let mut children = forest.children_of(0)?;
+ assert_eq!(children.next(), Some(1));
+ assert_eq!(children.next(), None);
+
+ // add more children
+
+ forest.plant(0, leaf!(2), false)?;
+ forest.plant(0, leaf!(3), false)?;
+ forest.plant(0, leaf!(4), false)?;
+ forest.plant(2, leaf!(5), false)?;
+
+ assert_eq!(forest.nodes_len(), 6);
+ let mut children = forest.children_of(0)?;
+ assert_eq!(children.next(), Some(1));
+ assert_eq!(children.next(), Some(2));
+ assert_eq!(children.next(), Some(3));
+ assert_eq!(children.next(), Some(4));
+ let mut children = forest.children_of(2)?;
+ assert_eq!(children.next(), Some(5));
+ assert_eq!(children.next(), None);
+
+ let mut test_forest = leaf!(0);
+ test_forest.plant(0, leaf!(1), false)?;
+ test_forest.plant(0, leaf!(2), false)?;
+ test_forest.plant(0, leaf!(3), false)?;
+ test_forest.plant(2, leaf!(5), false)?;
+
+ assert!(forest.is_prefix(0, &test_forest)?);
+
+ let mut test_forest = leaf!(0);
+ test_forest.plant(0, leaf!(1), false)?;
+ test_forest.plant(0, leaf!(2), false)?;
+ // this child of the root should have label 3 in order to be a
+ // prefix.
+ test_forest.plant(0, leaf!(4), false)?;
+ test_forest.plant(2, leaf!(5), false)?;
+
+ assert!(!forest.is_prefix(0, &test_forest)?);
+
+ let mut test_forest = leaf!(2);
+ test_forest.plant(0, leaf!(5), false)?;
+
+ assert!(forest.is_prefix(2, &test_forest)?);
+
+ // now test cloning
+
+ // add a duplicate label
+ forest.plant(3, leaf!(5), false)?;
+
+ assert_eq!(forest.nodes_len(), 6);
+
+ // add two children to 5
+
+ forest.plant(5, leaf!(6), false)?;
+ forest.plant(5, leaf!(7), false)?;
+
+ // clone and preserve one child
+ let cloned = forest.clone_node(5, 1, false)?;
+
+ assert_eq!(forest.nodes_len(), 10);
+
+ assert_eq!(forest.degree(cloned)?, 1);
+ assert_eq!(forest.degree(5)?, 2);
+
+ #[cfg(feature = "test-print-viz")]
+ forest.print_viz("forest.gv")?;
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_eq() -> Result<(), Box<dyn std::error::Error>> {
+ let mut forest = leaf!(0, usize);
+
+ forest.plant(0, leaf!(1), false)?;
+ forest.plant(0, leaf!(2), false)?;
+ forest.plant(0, leaf!(3), false)?;
+ forest.plant(0, leaf!(4), false)?;
+ forest.plant(2, leaf!(5), false)?;
+
+ let mut test_forest = leaf!(0);
+ test_forest.plant(0, leaf!(1), false)?;
+ test_forest.plant(0, leaf!(2), false)?;
+ test_forest.plant(0, leaf!(3), false)?;
+ test_forest.plant(2, leaf!(5), false)?;
+
+ assert_ne!(forest, test_forest);
+ assert_ne!(test_forest, forest);
+
+ test_forest.plant(0, leaf!(4), false)?;
+
+ assert_eq!(forest, test_forest);
+ assert_eq!(test_forest, forest);
+
+ Ok(())
+ }
+}
diff --git a/chain/src/item/default/splone.rs b/chain/src/item/default/splone.rs
new file mode 100644
index 0000000..1168539
--- /dev/null
+++ b/chain/src/item/default/splone.rs
@@ -0,0 +1,760 @@
+//! This module implements a function for "closing" and "splitting" a
+//! node in a forest, and hence the name.
+
+use super::*;
+use grammar::TNT;
+
+fn get_nt_label(label: GrammarLabel) -> Option<usize> {
+ match label.label() {
+ GrammarLabelType::TNT(TNT::Non(nt)) => Some(nt),
+ _ => None,
+ }
+}
+
+fn get_rule_label(label: GrammarLabel) -> Option<usize> {
+ match label.label() {
+ GrammarLabelType::Rule(rule) => Some(rule),
+ _ => None,
+ }
+}
+
+impl DefaultForest<ForestLabel<GrammarLabel>> {
+ /// Either "open split" or "closed split".
+ ///
+ /// An open split is an attempt to set the end of the node to
+ /// `None`, and a closed split is an attempt to set the end to a
+ /// specific position.
+ ///
+ /// Also this function preserves `edge_index + 1` many children
+ /// when splitting or cloning.
+ ///
+ /// To be more precise, this function performs the following
+ /// actions:
+ ///
+ /// 1. Make sure it is labelled by a nonterminal.
+ ///
+ /// 2. Check the status of the node. If it is packed, return an
+ /// error.
+ ///
+ /// 3. Make a new label according to the given `end`. See the
+ /// function
+ /// [`create_new_label`][DefaultForest::<ForestLabel<GrammarLabel>>::create_new_label]
+ /// for the process of making new labels.
+ ///
+ /// 4. If the new label is equal to the old label, and if
+ /// `edge_index + 1` is equal to the degree of the node, then do
+ /// nothing.
+ ///
+ /// 5. If the new label is equal to the old label but
+ /// `edge_index+1` is not equal to the degree of the node, then
+ /// clone the node while preserving `edge_index + 1` many
+ /// children.
+ ///
+ /// 6. If the new label is not equal to the old label, then split
+ /// the node. See the function
+ /// [`split_node`][DefaultForest::<ForestLabel<GrammarLabel>>::split_node]
+ /// for details.
+ ///
+ /// # Name
+ ///
+ /// The name is a mixture of *split* and *clone*.
+ ///
+ /// # NOTE
+ ///
+ /// We want to "do the same thing" to each parent of the node,
+ /// that should be checked to be labelled by a rule position.
+ ///
+ /// That is to say, if we replace the label of the node, we also
+ /// replace the label of the "rule parent". If we split the node,
+ /// the rule parents are also splitted in a parallel manner with
+ /// the splitted node.
+ ///
+ /// Also, when we refer to the parents of the node in the
+ /// descriptions of procedures below, we actually refer to the
+ /// parents of the rule parents, which should again be checked to
+ /// be labelled by non-terminals.
+ fn splone(&mut self, node: usize, end: Option<usize>, edge_index: usize) -> Result<(), Error> {
+ let node_label = self.vertex_label(node)?.ok_or(Error::NodeNoLabel(node))?;
+
+ assert!(get_nt_label(node_label.label()).is_some());
+
+ if node_label.is_packed() {
+ return Err(Error::SplitPack(node));
+ }
+
+ let node_end = node_label.label().end();
+ let node_degree = self.degree(node)?;
+
+ // We can check the end to know whether the new label is equal
+ // to the old label.
+ if node_end == end {
+ if node_degree == edge_index + 1 {
+ return Ok(());
+ }
+
+ dbg!();
+ self.clone_node(node, edge_index + 1, false)?;
+
+ return Ok(());
+ }
+
+ let new_label = self.create_new_label(node, end, edge_index)?;
+
+ let new_label = if let Some(label) = new_label {
+ label
+ } else {
+ return Ok(());
+ };
+
+ if node_end.is_some()
+ || edge_index + 1 != node_degree
+ || node_label.clone_index().is_some()
+ || new_label.clone_index().is_some()
+ {
+ return self.split_node(new_label, node, edge_index);
+ }
+
+ // replace the label directly
+
+ // if new_label.clone_index().is_none() {
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ builder.set_label(node, new_label)?;
+
+ let parents: Vec<_> = builder
+ .parents_of(node)?
+ .map(|parent| parent.node())
+ .collect();
+
+ for parent in parents {
+ let mut parent_label = builder
+ .vertex_label(parent)?
+ .ok_or(Error::NodeNoLabel(parent))?
+ .label();
+
+ assert!(get_rule_label(parent_label).is_some());
+ assert_eq!(builder.degree(parent)?, 1);
+
+ if let Some(pos) = end {
+ parent_label.set_end(pos);
+ } else {
+ parent_label.open_end();
+ }
+
+ let parent_label = ForestLabel::from(parent_label);
+
+ builder.set_label(parent, parent_label)?;
+ }
+ // } else {
+ // // REVIEW: Call `split_node` in this situation as well?
+
+ // // If we are here, the new label should have a packed
+ // // parent.
+ // let packed = self
+ // .query_label(ForestLabel::new(new_label.label(), ForestLabelType::Packed))
+ // .unwrap();
+
+ // let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ // builder.set_label(node, new_label)?;
+
+ // let parents: Vec<_> = builder.parents_of(node)?.collect();
+
+ // for parent in parents.iter() {
+ // builder.redirect(parent.node(), parent.edge(), packed)?;
+ // }
+
+ // builder.add_edge(packed, node, new_label)?;
+ // }
+
+ Ok(())
+ }
+
+ /// Procedure to split the node:
+ ///
+ /// 1. Create a new node with the new label.
+ ///
+ /// 2. Preserve the old children as specified by `edge_index + 1`.
+ ///
+ /// 3. For each parent, clone the parent. Replace the original
+ /// child of the parent, which pointed to the old node, by this
+ /// new node. Other children are inherited from the old parent.
+ fn split_node(
+ &mut self,
+ new_label: ForestLabel<GrammarLabel>,
+ mut node: usize,
+ edge_index: usize,
+ ) -> Result<(), Error> {
+ let end = new_label.label().end();
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut self.graph);
+
+ let mut new_node = builder.add_vertex(new_label);
+
+ let new_packed = if new_label.clone_index().is_some() {
+ let packed = builder
+ .query_label(ForestLabel::new(new_label.label(), ForestLabelType::Packed))
+ .unwrap();
+
+ builder.add_edge(packed, new_node, new_label)?;
+
+ Some(packed)
+ } else {
+ None
+ };
+
+ let preserve_children: Vec<_> = builder.children_of(node)?.take(edge_index + 1).collect();
+
+ for child in preserve_children {
+ builder.add_edge(new_node, child, new_label)?;
+ }
+
+ let parents: Vec<_> = {
+ if let Some(label) = self.vertex_label(node)? {
+ if 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());
+ assert_eq!(self.degree(parent.node())?, 1);
+
+ if let Some(pos) = end {
+ parent_label.set_end(pos);
+ } else {
+ parent_label.open_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 {
+ new_node = packed;
+ }
+
+ 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 self.has_same_children_but_one(
+ 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)?;
+ }
+ }
+
+ Ok(())
+ }
+
+ /// Procedure for the new label:
+ ///
+ /// 1. Copy the old label.
+ ///
+ /// 2. Set the end to `pos`.
+ ///
+ /// 3. Pack the label.
+ ///
+ /// 4. Check if this label already exists. If so, clone the label and
+ /// return it.
+ ///
+ /// 5. Else set the label to be a plain label.
+ ///
+ /// 6. Check if this plain label already exists. If so, clone the
+ /// existing label, and return the clone of the cloned label.
+ ///
+ /// 7. Else return the plain label.
+ fn create_new_label(
+ &mut self,
+ node: usize,
+ end: Option<usize>,
+ edge_index: usize,
+ ) -> Result<Option<ForestLabel<GrammarLabel>>, Error> {
+ let mut copied_label = self
+ .vertex_label(node)?
+ .ok_or(Error::NodeNoLabel(node))?
+ .label();
+
+ if let Some(pos) = end {
+ copied_label.set_end(pos);
+ } else {
+ copied_label.open_end();
+ }
+
+ let label = ForestLabel::new(copied_label, ForestLabelType::Packed);
+
+ if let Some(packed) = self.query_label(label) {
+ for child in self.children_of(packed)? {
+ if self.has_same_children(child, node, self.degree(child)?, edge_index + 1)? {
+ return Ok(None);
+ }
+ }
+
+ let mut packed_children = self.children_of(packed)?;
+
+ let first_child = packed_children.next().unwrap();
+
+ let clone_index = self.clone_node(first_child, 0, true)?;
+
+ Ok(Some(ForestLabel::new(
+ copied_label,
+ ForestLabelType::Cloned(clone_index),
+ )))
+ } else {
+ let plain_label = ForestLabel::new(copied_label, ForestLabelType::Plain);
+
+ if let Some(existing) = self.query_label(plain_label) {
+ if self.has_same_children(existing, node, self.degree(existing)?, edge_index + 1)? {
+ return Ok(None);
+ }
+
+ let clone_index = self.clone_node(existing, 0, true)?;
+
+ Ok(Some(ForestLabel::new(
+ copied_label,
+ ForestLabelType::Cloned(clone_index),
+ )))
+ } else {
+ Ok(Some(plain_label))
+ }
+ }
+ }
+
+ /// Compare if two nodes have the same children in the same order.
+ fn has_same_children(
+ &self,
+ nodea: usize,
+ nodeb: usize,
+ edge_num_a: usize,
+ edge_num_b: usize,
+ ) -> Result<bool, Error> {
+ let children_a = self.children_of(nodea)?.take(edge_num_a);
+ let children_b = self.children_of(nodeb)?.take(edge_num_b);
+
+ if children_a.len() != children_b.len() {
+ return Ok(false);
+ }
+
+ for (childa, childb) in children_a.zip(children_b) {
+ if childa != childb {
+ return Ok(false);
+ }
+ }
+
+ Ok(true)
+ }
+
+ /// Detect if a node has a branch that has the same children as
+ /// another node, except at a given index, where it points to
+ /// another given node.
+ fn has_same_children_but_one(
+ &self,
+ nodea: usize,
+ nodeb: usize,
+ edge_index: usize,
+ alternative: usize,
+ ) -> Result<bool, Error> {
+ let labela = self.vertex_label(nodea)?.ok_or(Error::NodeNoLabel(nodea))?;
+ let children_b = self.children_of(nodeb)?;
+
+ if labela.is_plain() {
+ let children_a = self.children_of(nodea)?;
+
+ if children_a.len() != children_b.len() {
+ return Ok(false);
+ }
+
+ for (index, (childa, childb)) in children_a.zip(children_b).enumerate() {
+ if index != edge_index {
+ if childa != childb {
+ return Ok(false);
+ }
+ } else if childa != alternative {
+ return Ok(false);
+ }
+ }
+
+ Ok(true)
+ } else if labela.clone_index().is_some() {
+ let mut parentsa = self.parents_of(nodea)?;
+
+ assert_eq!(parentsa.len(), 1);
+
+ let parenta = parentsa.next().unwrap().node();
+
+ 'branch_loop: for branch in self.children_of(parenta)? {
+ let children_a = self.children_of(branch)?;
+ let children_b = children_b.clone();
+
+ if children_a.len() != children_b.len() {
+ continue 'branch_loop;
+ }
+
+ for (index, (childa, childb)) in children_a.zip(children_b).enumerate() {
+ if index != edge_index {
+ if childa != childb {
+ continue 'branch_loop;
+ }
+ } else if childa != alternative {
+ continue 'branch_loop;
+ }
+ }
+
+ return Ok(true);
+ }
+
+ Ok(false)
+ } else {
+ // a packed node; this should not happen
+ unreachable!("should not examine children of a packed node")
+ }
+ }
+}
+
+#[cfg(test)]
+mod test_splone {
+ use super::*;
+
+ use grammar::TNT::*;
+
+ fn create_test_forest(
+ ) -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>> {
+ let mut forest = leaf!(GrammarLabel::new(Non(0), 0), GrammarLabel);
+
+ forest.plant(
+ 0,
+ leaf!(GrammarLabel::new_closed(6, 0, 1), GrammarLabel),
+ false,
+ )?;
+ forest.plant(
+ 1,
+ leaf!(GrammarLabel::new_closed(Ter(0), 0, 1), GrammarLabel),
+ false,
+ )?;
+
+ forest.plant(0, leaf!(GrammarLabel::new(7, 1), GrammarLabel), false)?;
+ forest.plant(3, leaf!(GrammarLabel::new(Non(0), 1), GrammarLabel), false)?;
+
+ forest.plant(4, leaf!(GrammarLabel::new(3, 1), GrammarLabel), false)?;
+ forest.plant(5, leaf!(GrammarLabel::new(Non(1), 1), GrammarLabel), false)?;
+
+ forest.plant(
+ 6,
+ leaf!(GrammarLabel::new_closed(11, 1, 2), GrammarLabel),
+ false,
+ )?;
+ forest.plant(
+ 7,
+ leaf!(GrammarLabel::new_closed(Ter(2), 1, 2), GrammarLabel),
+ false,
+ )?;
+
+ forest.plant(
+ 6,
+ leaf!(GrammarLabel::new_closed(13, 2, 3), GrammarLabel),
+ false,
+ )?;
+ forest.plant(
+ 9,
+ leaf!(GrammarLabel::new_closed(Ter(2), 2, 3), GrammarLabel),
+ false,
+ )?;
+
+ forest.print_viz("test forest.gv")?;
+
+ Ok(forest)
+ }
+
+ fn splone_6_3_1() -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>>
+ {
+ let mut forest = create_test_forest()?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ builder.set_label(
+ 5,
+ ForestLabel::new(GrammarLabel::new_closed(3, 1, 3), ForestLabelType::Plain),
+ )?;
+
+ builder.set_label(
+ 6,
+ ForestLabel::new(
+ GrammarLabel::new_closed(Non(1), 1, 3),
+ ForestLabelType::Plain,
+ ),
+ )?;
+
+ Ok(forest)
+ }
+
+ fn splone_6_2_0() -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>>
+ {
+ let mut forest = splone_6_3_1()?;
+
+ let cloned = forest.clone_node(4, 0, false)?;
+
+ forest.plant(
+ cloned,
+ leaf!(GrammarLabel::new_closed(3, 1, 2), GrammarLabel),
+ false,
+ )?;
+
+ forest.plant(
+ cloned + 1,
+ leaf!(GrammarLabel::new_closed(Non(1), 1, 2), GrammarLabel),
+ false,
+ )?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ let dummy_label = ForestLabel::from(GrammarLabel::new(0, 0));
+
+ builder.add_edge(cloned + 2, 7, dummy_label)?;
+
+ Ok(forest)
+ }
+
+ fn splone_6_n_0() -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>>
+ {
+ let mut forest = splone_6_2_0()?;
+
+ let cloned = forest.clone_node(4, 0, false)?;
+
+ forest.plant(cloned, leaf!(GrammarLabel::new(3, 1), GrammarLabel), false)?;
+
+ forest.plant(
+ cloned + 1,
+ leaf!(GrammarLabel::new(Non(1), 1), GrammarLabel),
+ false,
+ )?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ let dummy_label = ForestLabel::from(GrammarLabel::new(0, 0));
+
+ builder.add_edge(cloned + 2, 7, dummy_label)?;
+
+ Ok(forest)
+ }
+
+ fn splone_4_3_0() -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>>
+ {
+ let mut forest = splone_6_n_0()?;
+
+ let cloned = forest.clone_node(0, 0, false)?;
+
+ forest.plant(
+ cloned,
+ leaf!(GrammarLabel::new_closed(7, 1, 3), GrammarLabel),
+ false,
+ )?;
+
+ forest.plant(
+ cloned + 1,
+ leaf!(GrammarLabel::new_closed(Non(0), 1, 3), GrammarLabel),
+ false,
+ )?;
+
+ forest.plant(
+ cloned,
+ leaf!(GrammarLabel::new_closed(6, 0, 1), GrammarLabel),
+ true,
+ )?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ let dummy_label = ForestLabel::from(GrammarLabel::new(0, 0));
+
+ builder.add_edge(cloned + 2, 5, dummy_label)?;
+
+ Ok(forest)
+ }
+
+ fn splone_17_3_0_15_3_0(
+ ) -> Result<DefaultForest<ForestLabel<GrammarLabel>>, Box<dyn std::error::Error>> {
+ let mut forest = splone_4_3_0()?;
+
+ let to_clone = forest
+ .query_label(ForestLabel::from(GrammarLabel::new_closed(Non(1), 1, 3)))
+ .unwrap();
+
+ let cloned = forest.clone_node(to_clone, 0, false)?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ let dummy_label = ForestLabel::from(GrammarLabel::new(0, 0));
+
+ let child = builder
+ .query_label(ForestLabel::from(GrammarLabel::new_closed(11, 1, 2)))
+ .unwrap();
+
+ builder.add_edge(cloned, child, dummy_label)?;
+
+ let to_clone = forest
+ .query_label(ForestLabel::from(GrammarLabel::new_closed(Non(0), 1, 3)))
+ .unwrap();
+
+ let cloned = forest.clone_node(to_clone, 0, false)?;
+
+ let mut builder = PLGBuilderMut::from_graph_mut(&mut forest.graph);
+
+ let child = builder
+ .query_label(ForestLabel::from(GrammarLabel::new(3, 1)))
+ .unwrap();
+
+ builder.add_edge(cloned, child, dummy_label)?;
+
+ Ok(forest)
+ }
+
+ #[test]
+ fn test() -> Result<(), Box<dyn std::error::Error>> {
+ let mut test_forest = create_test_forest()?;
+
+ test_forest.splone(6, Some(3), 1)?;
+
+ let answer = splone_6_3_1()?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 3 1.gv")?;
+ panic!("splone(6, Some(3), 1) produced wrong forest");
+ }
+
+ test_forest.splone(6, Some(3), 1)?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 3 1.gv")?;
+ panic!("repeated splone(6, Some(3), 1) produced wrong forest");
+ }
+
+ test_forest.splone(6, Some(2), 0)?;
+
+ let answer = splone_6_2_0()?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 2 0.gv")?;
+ panic!("splone(6, Some(2), 0) produced wrong forest");
+ }
+
+ test_forest.splone(6, Some(2), 0)?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 2 0.gv")?;
+ panic!("repeated splone(6, Some(2), 0) produced wrong forest");
+ }
+
+ test_forest.splone(6, None, 0)?;
+
+ let answer = splone_6_n_0()?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 None 0.gv")?;
+ panic!("splone(6, None, 0) produced wrong forest");
+ }
+
+ test_forest.splone(14, None, 0)?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 6 None 0.gv")?;
+ panic!("repeated splone(6, None, 0) produced wrong forest");
+ }
+
+ test_forest.splone(4, Some(3), 0)?;
+
+ let answer = splone_4_3_0()?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 4 3 0.gv")?;
+ panic!("splone(4, Some(3), 0) produced wrong forest");
+ }
+
+ test_forest.splone(4, Some(3), 0)?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 4 3 0.gv")?;
+ panic!("repeated splone(4, Some(3), 0) produced wrong forest");
+ }
+
+ test_forest.splone(17, Some(3), 0)?;
+ test_forest.splone(15, Some(3), 0)?;
+
+ let answer = splone_17_3_0_15_3_0()?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 17 3 0 15 3 0.gv")?;
+ panic!("splone(17, Some(3), 0) - splone(15, Some(3), 0) produced wrong forest");
+ }
+
+ test_forest.splone(17, Some(3), 0)?;
+ test_forest.splone(15, Some(3), 0)?;
+
+ if test_forest != answer {
+ test_forest.print_viz("sploned forest.gv")?;
+ answer.print_viz("splone 17 3 0 15 3 0.gv")?;
+ panic!(
+ "repeated splone(17, Some(3), 0) - splone(15, Some(3), 0) produced wrong forest"
+ );
+ }
+
+ Ok(())
+ }
+}