批次：从SETLOCAL EnableDelayedExpansion返回值 [英] Batch: Returning a value from a SETLOCAL EnableDelayedExpansion

问题描述

我不知道为什么因为预计今年code不工作：

  @ECHO关闭
SET S1 = HELLOSETLOCAL EnableDelayedExpansion
SET S2 =！S1！世界^^！
ECHO！S2！
ENDLOCAL＆安培; SET S1 =！S2！ECHO％S1％
暂停
 

输出：

 世界，你好！
！S2！
 

期望的输出：

 世界，你好！
你好，世界！
 

感谢。

解决方案

据按预期工作。结果
延迟的扩张将在执行时扩展变量，而不是解析时间，因此除preT你行 ENDLOCAL＆安培; SET S1 =！S2！的结果
ENDLOCAL 结果
但在 SET S1的部分=！S2！延迟扩展关闭，因此它不能再扩大了。

在你的情况，你可以使用
ENDLOCAL＆安培; SET S1 = S2％％

由于感叹号S2是安全，作为延迟EXP。是关在执行的时刻。

但是，一个永远安全的返回是更复杂一点。结果
我们讨论它在 Dostips：返回跨ENDLOCAL疆

I wonder why this code does not work as expected:

@ECHO off
SET S1=HELLO

SETLOCAL EnableDelayedExpansion
SET S2=!S1! WORLD^^!
ECHO !S2!
ENDLOCAL & SET S1=!S2!

ECHO %S1%
PAUSE

Output:

HELLO WORLD!
!S2!

Expected output:

HELLO WORLD!
HELLO WORLD!

Thanks.

解决方案

It works as expected.
The delayed expansion will expand variables at execution time, not parse time, so it interpret your line ENDLOCAL & SET S1=!S2! as
endlocal
But at the part of SET S1=!S2! the delayed expansion is off so it can't be expanded anymore.

In your case you could use ENDLOCAL & SET S1=%S2%

As the exclamation mark is S2 is "safe", as the delayed exp. is off at the moment of execution.

But an always secure returning is a bit more complicated.
We discussed it at Dostips: Return ANY string across ENDLOCAL boundry

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