static S snlToText(S s) {
  ret snlToText(snlToTree(s));
}

static S snlToText(Lisp tree) {
  if (tree == null) ret "";
  tree = snlRemoveReferences(tree);
  
  if (snlToText_isJuxta(tree))
    tree = snlToText_addDots(tree);
  
  tree = snlQuestionMarksToBack(tree);
  
  S snl = snlFromTree(tree);
  new StringBuilder buf;
  L<S> drop = litlist ("[", "]", "<", ">");
  for (S t : codeTokensOnly(snlTok(snl)))
    if (!drop.contains(t)) {
      if (buf.length() != 0 && !litlist(".", "?").contains(t))
        buf.append(" ");
      buf.append(t);
    }
  ret str(buf);
}

static boolean snlToText_isJuxta(Lisp tree) {
  ret eq("*", join(asList(new HashSet<S>(codeTokensOnly(javaTok(tree.head))))));
}

static Lisp snlToText_addDots(Lisp tree) {
  Lisp t = new Lisp(tree.head);
  for (Lisp x : tree) {
    if (x.isA("<") && !x.get(0).is("?", "."))
      x = lisp("<", ".", x);
    t.add(x);
  }
  ret t;
}