text: <?php
  
  namespace dokuwiki\plugin\config\core\Setting;
  
  /**
   * Class setting_numericopt
   */
  class SettingNumericopt extends SettingNumeric {
      // just allow an empty config
      protected $pattern = '/^(|[-]?[0-9]+(?:[-+*][0-9]+)*)$/';
  
      /**
       * @inheritdoc
       * Empty string is valid for numericopt
       */
      public function update($input) {
          if($input === '') {
              if($input == $this->local) return false;
              $this->local = $input;
              return true;
          }
  
          return parent::update($input);
      }
  }
  