public function trimBalanced($openChar, $closeChar) { $stLen = mb_strlen($openChar); $endLen = mb_strlen($closeChar); while ($this->startsWith($openChar) && $this->endsWith($closeChar)) { $this->value = mb_substr($this->value, $stLen, $this->length - ($stLen + $endLen)); $this->length -= $stLen + $endLen; } return $this; }