title: Antlr4 Can I listen to my own visitor?
body: <ul>
  <li>I understand that Antlr generates a tree walker and I can sub-class the <code>BaseListener</code> to act when the tree walker traverses over key items in the parse tree.</li>
  <li>I understand that I can also create my own visitor, by sub-class <code>BaseVisitor</code> to navigate the parse tree in my own way.</li>
  </ul>
  
  <p>Can I have my listener that responds to my own visitor?<br> I think I made a boo-boo and placed my application code unnecessarily in my sub-classed visitor.
  <p>
  I now believe the visitor should only visit and my listener should trigger events in my application code.
  <p>
  I think I got a little bit muddled in my implementation. </p>