public static String toStringTree(Tree t) {
		return toStringTree(t, (List<String>)null);
	}
Print out a whole tree in LISP form. {@link #getNodeText} is used on the
 node payloads to get the text for the nodes.  Detect
 parse trees and extract data appropriately.
runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java