public int compare(@Nullable String lhs, @Nullable String rhs) {
      if (lhs == rhs) {
        return 0;
      }
      if (lhs == null) {
        // lhs (null) comes just before justAfterNull.
        // If rhs is b, lhs comes first.
        if (rhs.equals(justAfterNull)) {
          return -1;
        }
        return justAfterNull.compareTo(rhs);
      }
      if (rhs == null) {

    public int compare(@Nullable String lhs, @Nullable String rhs) {
      if (lhs == rhs) {
        return 0;
      }
      if (lhs == null) {
        // lhs (null) comes just before justAfterNull.
        // If rhs is b, lhs comes first.
        if (rhs.equals(justAfterNull)) {
          return -1;
        }
        return justAfterNull.compareTo(rhs);
      }
      if (rhs == null) {

	default:
		return nil, errInvalidASTNode
	}
	rhs = *eltVal

	// If RHS is array compare each element.
	if arr, ok := rhs.ToArray(); ok {
		for _, element := range arr {
			// If we have an array we are on the wrong level.
			if cmp(element, *lhs) {
				return FromBool(true), nil
			}
		}
		return FromBool(false), nil
	}

	return FromBool(cmp(rhs, *lhs)), nil
}