带常量的 PHP 类变量

Question

我在常量 (DEPLOYMENT) 行上收到解析错误。为什么现在允许这样做，或者我错过了什么。

解析错误：解析错误，期望出现“')'”

class UploadComponent extends Object {

    private $config = array(
        'accessKey' => 'XXXX',
        'secretKey' => 'XXXX',

        'images' => array(
            'bucket' => DEPLOYMENT.'-files/images',
            'dns' => false
        ),

        'files' => array(
            'bucket' => DEPLOYMENT.'-files/files',
            'dns' => false
        ),

        'assets' => array(
            'bucket' => DEPLOYMENT.'-files/assets',
            'dns' => false
        )
    );
    ....
}

Answer 1

定义类变量时不能使用变量。相反，请在构造函数内初始化数组：

class UploadComponent extends Object {

    private $config;

    function __construct() {
        $this->config = array(
            'accessKey' => 'XXXX',
            'secretKey' => 'XXXX',

            'images' => array(
                'bucket' => DEPLOYMENT.'-files/images',
                'dns' => false
            ),

            'files' => array(
                'bucket' => DEPLOYMENT.'-files/files',
                'dns' => false
            ),

            'assets' => array(
                'bucket' => DEPLOYMENT.'-files/assets',
                'dns' => false
            )
        );
    }
}

Answer 2

原因是“常量”可以动态定义。因此，它们的内容只能在运行时知道，而不能在编译时知道。