// AST nodes have payload that point into token stream
nodes.setTokenStream(tokens);
// Create a tree walker attached to the nodes stream
treeParser = classForName(treeParserPath).asSubclass(TreeParser.class);
Constructor<? extends TreeParser> treeParConstructor = treeParser.getConstructor(TreeNodeStream.class);
TreeParser treeParObj = treeParConstructor.newInstance(nodes); // makes new instance of tree parser
// Invoke the tree rule, and store the return value if there is
Method treeRuleName = treeParser.getMethod(testTreeRuleName);
Object treeRuleReturn = treeRuleName.invoke(treeParObj);
String astString = null;