code: function toString()
      {
          return "Rule [isCustomfield=" . ($this->isCustomfield) ? "true" : "false" . ", field=" . $this->field . ", operator=" . $this->operator . ", value=" . $this->value . " (type = " . $this->type . ")";
      }
docs: Human readable representation of this rule.
  
  @return \em string
  A human readable version of the rule.