public function parse($arguments)
    {
        if (!is_array($arguments)) {
            $arguments = explode(' ', $arguments);
        }
        $operands = array();
        $numArgs = count($arguments);
        for ($i = 0; $i < $numArgs; ++$i) {
            $arg = trim($arguments[$i]);
            if (empty($arg)) {
                continue;
            }
            if (($arg === '--') || ($arg === '-') || (mb_substr($arg, 0, 1) !== '-')){
                // no more options, treat the remaining arguments as operands
                $firstOperandIndex = ($arg == '--') ? $i + 1 : $i;
                $operands = array_slice($arguments, $firstOperandIndex);
                break;
            }
            if (mb_substr($arg, 0, 2) == '--') {
                $this->addLongOption($arguments, $i);
            } else {
                $this->addShortOption($arguments, $i);
            }
        } // endfor

        $this->addDefaultValues();

        // remove '--' from operands array
        foreach ($operands as $operand) {
            if ($operand !== '--') {
                $this->operands[] = $operand;
            }
        }
    }