return expr._boolean(node, expr.evaluate(node, pos, len));
return Expr._boolean(node, expr.evaluate(node, pos, len));
  public boolean matches(Node node, int pos, int len)  {    Object ret = expr.evaluate(node, pos, len);    if (ret instanceof Double)      {        // Same as [position() = x]        return ((Double) ret).intValue() == pos;      }    return expr._boolean(node, expr.evaluate(node, pos, len));  }