protected function convertOperation($expr1, $operator, $expr2)
	{
		$expr1 = $this->convert($expr1);
		$expr2 = $this->convert($expr2);

		// Prevent two consecutive minus signs to be interpreted as a post-decrement operator
		if ($operator === '-' && $expr2[0] === '-')
		{
			$operator .= ' ';
		}

		return $expr1 . $operator . $expr2;
	}