英文:
PHP numeric casing with goto
问题
我愉快地发现在PHP中可以使用goto：
case 222: return "A"; break;
case 231: return "B"; break;
case 234: goto 231;
case 237: return "C"; break;
case 251: goto 231;
case 285: return "D"; break;
我有一些类似这样的代码。有很多键共享相同的值，所以我试图使用goto来消除冗余。我在这里使用switch，因为它比if/else分支更简单。
出于各种原因，每种情况都必须像上面一样明确定义，即使它只是转到另一个情况。然而，将此通过验证器运行时，我收到Parse error: syntax error, unexpected '231' (T_CONSTANT_ENCAPSED_STRING), expecting identifier (T_STRING) in your code错误消息。
我尝试将情况用单引号括起来，但仍然无法通过。这似乎与上面的示例一致。在语法方面我漏掉了什么？
英文:
I pleasantly found that it is possible to use goto in PHP:
case 222: return "A"; break;
case 231: return "B"; break;
case 234: goto 231;
case 237: return "C"; break;
case 251: goto 231;
case 285: return "D"; break;
I have some code like this. There are a lot of keys that shared the same value, so I am trying to use goto to eliminate redundancy. I'm use a switch since it's simpler here than if/else branching.
For various reasons, each case must be explicitly defined as above, even if it just goes to another case. However, running this through a validator, I get Parse error: syntax error, unexpected ''231'' (T_CONSTANT_ENCAPSED_STRING), expecting identifier (T_STRING) in your code
I tried surrounding the cases with single quotes, but that still didn't pass. This seems in line with the example above. What am I missing syntax-wise here?
答案1
得分: 1
标签不能仅为数字，所以您只能通过为要定位的“cases”创建额外的标签（并修改“gotos”以使用这些新标签）来解决该问题：
function foo($value) {
switch ($value) {
case 222:
return "A";
case 231:
label231: // 在这里添加新标签
return "B";
case 234:
goto label231;
case 237:
return "C";
case 251:
goto label231;
case 285:
return "D";
}
}
var_dump(foo(251));
然而，正如评论中提到的，我更喜欢选择不同的方法（例如关联数组等）。
英文:
Label cannot be numeric only, so you could only solve it by creating extra label for cases you want to target (and also modifying gotos with those new labels):
<?php
function foo($value) {
switch ($value) {
case 222:
return "A";
case 231:
label231: // new label here
return "B";
case 234:
goto label231;
case 237:
return "C";
case 251:
goto label231;
case 285:
return "D";
}
}
var_dump(foo(251));
However as mentioned in the comments, I would prefer choosing a different approach (associative array etc.).
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