chain/atom/default: add a function to print virtual nodes.

* chain/src/atom/default.rs (print_virtual): Previously printing
  virtual nodes is done inside the function `print_nfa`; now this is
  decoupled and thus more flexible.

1 files changed, 13 insertions, 14 deletions

diff --git a/chain/src/atom/default.rs b/chain/src/atom/default.rs
index 85d652f..e156178 100644
--- a/chain/src/atom/default.rs
+++ b/chain/src/atom/default.rs
@@ -131,25 +131,24 @@ impl DefaultAtom {
         println!();
     }
 
+    /// Print virtual nodes.
+    pub fn print_virtual(&self) {
+        println!("printing virtual nodes of the atom:");
+
+        for (vn, node) in self.virtual_nodes.iter() {
+            println!("[{}]^{{({})}}: {}", vn.s, vn.t, node);
+        }
+
+        println!();
+    }
+
     /// Print the underlying NFA.
     pub fn print_nfa<S: AsRef<str>>(&self, filename: S) -> Result<(), std::io::Error> {
         self.nfa.print_viz(filename.as_ref())?;
 
-        let nullables: Vec<_> = self
-            .accepting_vec
-            .iter()
-            .enumerate()
-            .filter_map(|(index, pred)| if *pred { Some(index) } else { None })
-            .collect();
-
-        if !nullables.is_empty() {
-            println!("nullables: {nullables:?}");
-        }
+        self.print_nullables();
 
-        println!("printing virtual nodes:");
-        for (vn, node) in self.virtual_nodes.iter() {
-            println!("[{}]^{{({})}}: {}", vn.s, vn.t, node);
-        }
+        self.print_virtual();
 
         Ok(())
     }