protected function fetchChoice($choices, $index, $count)
    {
        $choice = $choices[$index];

        // Set from number, if not set (notation ":X").
        if (!$choice->range->from) {
            if ($index > 0) {
                $choice->range->from = ($choices[($index - 1)]->range->to + 1);
            } else {
                $choice->range->from = (-PHP_INT_MAX);
            }
        }
        // Set to number, if not set (notation "X" or "X:").
        if (!$choice->range->to) {
            if ($index < ($count - 1)) {
                $choice->range->to = ($choices[($index + 1)]->range->from - 1);
            } else {
                $choice->range->to = PHP_INT_MAX;
            }
        }

        return $choice;
    }