不！

Question

包含文件中是否可能包含不完整的语句。例如就我而言，我想重复这段代码->

case "c":
case "d":
case "e":

我将其放置在包含文件file.inc.php

中

<?php
case "c":
case "d":
case "e":

，正常的运行代码是这样的：

switch {

 case "a":
 case "b":
  //something gets done here!
  break;

 include ('file.inc.php');
  //do something here - doesn't work tho
  break;

}

可以做到吗？从我所看到的，我什至不确定包含文件是否包含在内？开关仅查找a和b，没有错误。

Answer 1

请阅读php手册以了解开关情况。我认为您的代码无法使用这种语法。

https://www.php.net/manual/en/control-structures.switch.php

switch {

 case "a":
 case "b":
   //something gets done here!
   break;
 case "c":
   include ('file.inc.php');
   //do something here - doesn't work tho
   break;
}

Answer 2

是否可以将案例导入切换块？

是。

您应该实施吗？

不！

正如我之前许多人所强调的那样，eval()是“邪恶的”，并且闪烁着巨大的征兆，即您的项目结构有些尴尬/不合适。最后，您应该花时间重构项目，以便不再需要此技术。

现在，为了证明这是可能的...一种解决方法是将include()调用替换为file_get_contents调用以获取包含文件的内容，并将该字符串作为一个完整字符串插入switch()使用eval()进行阻止。

经过测试的代码：

broken_switch.php

<?php
$includedCases = file_get_contents('evaled.inc.php');
foreach (['a', 'b', 'c', 'd', 'e', 'f'] as $letter) {
    echo "<div> $letter => ";

    eval('
        switch ($letter) {
            case "a":
            case "b":
                echo "switch value satisfied by a or b as normal";
                break;          
            ?>' . $includedCases . '
                echo "switch value satisfied by c, d, or e from eval\'ed include file";
                break;
            default:
                echo "default case";        
        }
    ');
    echo "</div>";
}

evaled.inc.php

<?php
case "c":
case "d":
case "e":

broken_switch.php 的输出：

a => switch value satisfied by a or b as normal
b => switch value satisfied by a or b as normal
c => switch value satisfied by c, d, or e from eval'ed include file
d => switch value satisfied by c, d, or e from eval'ed include file
e => switch value satisfied by c, d, or e from eval'ed include file
f => default case

这只是一个示范。我不会打扰“优化”，因为我要指出的是该技术不应实施。

在转换案例声明中包含文件

2 个答案:

是。

不！