static boolean putMatchX(Map<S, Lisp> matches, S key, Lisp val) {
  if (matches.containsKey(key) && neq(matches.get(key), val)) {
    print ("key: " + key);
    fail("multi-matching not implemented");
  }
  matches.put(key, val);
  ret true;
}

static boolean putMatchX(Map<S, Lisp> matches, S key, S val) {
  ret putMatchX(matches, key, lisp(val));
}

static boolean putMatchX(Map<S, Lisp> mOuter, Map<S, Lisp> mInner, S key, S val) {
  // TODO: if it points to a literal
  ret putMatchX(mOuter, mInner.get(key).raw(), val);
}