php – 使用heredoc语法访问字符串中的静态变量的正确方法？

假设我的班级中有一个名为$_staticVar的静态变量,我试图像这样访问.该变量有一个成员aString,其字符串值为“my static variable”

    echo <<<eos

    <br/>This is the content of my static variable, 
    self::$_staticVar->$aString
    which is not getting accessed properly in heredoc syntax. <br/>

eos;

输出：

Notice: Undefined variable: _staticVar in /path/to/file.php on line some_line_number

<br/>This is the content of my static variable,
self::->my static variable,
which is not getting accessed properly in heredoc syntax.<br/>

heredoc PHP^docs对此没有任何说明.

我试过这个：

    echo <<<eos

    <br/>This is the content of my static variable,<br/>
    {${self::$_staticVar->$aString}}<br/>
    which is not getting accessed properly in heredoc syntax. <br/>

eos;

它不起作用.
输出：

Notice: Undefined variable: _staticVar in /path/to/file.php on line some_line_number

<br/>This is the content of my static variable,
   
which is not getting accessed properly in heredoc syntax.<br/>

这是我的PHP设置：

display_startup_errors = on
display_errors = On
error_reporting = E_ALL | E_STRICT

解决方法:

我很确定你必须使用本地或导入的变量进行字符串插值.最简单的解决方案？为什么,当然是当地的：

    $_staticVar = self::$_staticVar; // or did you mean self::_staticVar? Not too clear on that.

    echo <<<eos

    <br/>Something {$_staticVar->something} more of something <br/>

eos;

至于你的例子不起作用的原因：

    echo <<<eos

    <br/>Something self::$_staticVar->{$something} more of something <br/>

eos;

插入未定义的变量$something和$_staticVar,这会产生一个空字符串和一个通知.

    echo <<<eos

    <br/>Something {${self::$$_staticVar->{$something}}} more of something <br/>

eos;

插值绝对不存在但永远不会存在的东西,这一切都让人感到困惑,但你知道它不起作用.

标签：heredoc,php,string
来源： https://codeday.me/bug/20191007/1865333.html