Added the functionality of split or clone.

I need more than the ability to clone nodes: I also need to split the
nodes.  Now this seems to be correctly added.

1 files changed, 32 insertions, 1 deletions

diff --git a/chain/src/default.rs b/chain/src/default.rs
index 5e94623..31c1002 100644
--- a/chain/src/default.rs
+++ b/chain/src/default.rs
@@ -38,6 +38,8 @@ pub enum Error {
     CannotPlant,
     /// Trying to insert an empty item.
     EmptyItem,
+    /// Cannot split a packed node.
+    SplitPack(usize),
     /// An invalid situation happens.
     Invalid,
 }
@@ -56,6 +58,7 @@ impl Display for Error {
             Self::CannotClone(fe) => write!(f, "cannot clone due to {fe}"),
             Self::CannotPlant => write!(f, "cannot plant a new forest fragment"),
             Self::EmptyItem => write!(f, "trying to insert an empty item"),
+            Self::SplitPack(n) => write!(f, "cannot split the packed node {n}"),
             Self::Invalid => write!(f, "invalid"),
         }
     }
@@ -82,6 +85,7 @@ impl From<ForestError> for Error {
             ForestError::InvalidGraphError(ge) => ge.into(),
             ForestError::NodeNoLabel(n) => Error::NodeNoLabel(n),
             ForestError::LabelConversion(ce) => Error::CannotClone(ce),
+            ForestError::SplitPack(n) => Error::SplitPack(n),
         }
     }
 }
@@ -783,7 +787,6 @@ mod test_chain {
 
         let mut chain = DefaultChain::unit(atom)?;
         chain.chain(3, 00)?;
-        dbg!("hi");
         chain.chain(1, 01)?;
         chain.chain(2, 02)?;
         chain.chain(2, 03)?;
@@ -811,6 +814,34 @@ mod test_chain {
     }
 
     #[test]
+    fn test_ambiguity() -> Result<(), Box<dyn std::error::Error>> {
+        let grammar = new_paren_grammar()?;
+
+        let atom = DefaultAtom::from_grammar(grammar)?;
+
+        let mut chain = DefaultChain::unit(atom)?;
+        chain.chain(0, 0)?;
+        chain.chain(2, 1)?;
+        chain.chain(2, 2)?;
+        // chain.chain(2, 3)?;
+        chain.chain(1, 3)?;
+
+        dbg!(chain.current(), chain.history());
+
+        #[cfg(feature = "test-print-viz")]
+        {
+            chain.graph.print_viz("chain.gv")?;
+            chain.atom.print_nfa("nfa.gv")?;
+            chain.forest.print_viz("forest.gv")?;
+            item::default::print_labels(&chain.atom, &chain.forest)?;
+        }
+
+        assert!(matches!(chain.epsilon(), Ok(true)));
+
+        Ok(())
+    }
+
+    #[test]
     fn test_speed() -> Result<(), Box<dyn std::error::Error>> {
         let grammar = new_notes_grammar_no_regexp()?;