1 files changed, 15 insertions, 5 deletions
diff --git a/nfa/src/default/regex.rs b/nfa/src/default/regex.rs
index 2670e32..c8ad370 100644
--- a/nfa/src/default/regex.rs
+++ b/nfa/src/default/regex.rs
@@ -260,9 +260,7 @@ impl<T: GraphLabel> DefaultRegex<T> {
         stack.push(Unseen(0));
 
         while let Some(top) = stack.pop() {
-            let node_type = types[top.index()];
-
-            // TODO: Do not use unwrap here.
+            let node_type = types.get(top.index()).unwrap();
 
             match node_type {
                 RegexType::Kleene => {
@@ -350,8 +348,12 @@ impl<T: GraphLabel> DefaultRegex<T> {
                             .map(Unseen)
                             .rev(),
                     );
+
+                    if self.graph.is_empty_node(top.index()).unwrap() {
+                        write!(result, "ε")?;
+                    }
                 }
-                RegexType::Lit(label) => write!(result, "{}", f(label))?,
+                RegexType::Lit(label) => write!(result, "{}", f(*label))?,
             }
         }
 
@@ -452,7 +454,15 @@ impl Display for ParseError {
     }
 }
 
-impl std::error::Error for ParseError {}
+impl std::error::Error for ParseError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        if let ParseError::Graph(gerr) = self {
+            Some(gerr)
+        } else {
+            None
+        }
+    }
+}
 
 impl From<GError> for ParseError {
     fn from(ge: GError) -> Self {