ArrayAccess 多维（未）设置

php
class MultiDimensionalArray implements ArrayAccess
{
    private $data = [];
    public function offsetExists($offset)
    {
        return isset($this->data[$offset]);
    }
    public function offsetGet($offset)
    {
        return $this->data[$offset];
    }
    public function offsetSet($offset, $value)
    {
        if (is_array($offset)) {
            $this->setMultiDimensionalValue($this->data, $offset, $value);
        } else {
            $this->data[$offset] = $value;
        }
    }
    public function offsetUnset($offset)
    {
        unset($this->data[$offset]);
    }
    private function setMultiDimensionalValue(&$data, $keys, $value)
    {
        $key = array_shift($keys);
        if (count($keys) == 0) {
            $data[$key] = $value;
        } else {
            if (!isset($data[$key])) {
                $data[$key] = [];
            }
            $this->setMultiDimensionalValue($data[$key], $keys, $value);
        }
    }
}
// 示例用法
$array = new MultiDimensionalArray();
$array['key1']['key2'] = 'value';
echo $array['key1']['key2'];  // 输出：value