如何将变量的值保留在使用“延迟扩展本地”的Windows批处理脚本之外模式？

问题描述

限时删除！！

上下文：我需要调用Windows批处理脚本，通过添加另一个路径' xxx来更新我的 PATH




没有任何重复

（if我添加' xxx '到PATH，像' aaa; xxx; bbb '，我需要一个更新的 PATH 喜欢' aaa; bbb; xxx '）

没有任何聚合

（我可以重复地调用脚本，而不用' aaa; bbb; xxx; xxx; xxx; ... '）

我尝试过：

以下函数负责重复任务， / p>

 ：cleanAddPath  - 从PATH中删除％〜1，将其添加到PATH结尾
 SETLOCAL ENABLEDELAYEDEXPANSION 
设置PATH =！PATH：％〜2 =！ 
 set PATH =！PATH：;; =;！ 
设置PATH =％PATH％;％〜2 
设置P =！P：;; = 
 echo％PATH％
 echo ------------- 
 ENDLOCAL 
退出/ b 
  / pre> 
 
 
但是，它需要，这意味着：在脚本结束（或这里，函数结束时 cleanAddPath ），任何为％PATH％设置的东西被抛弃。
 
 
 
我可以问用户为此，您可以使用 cmd / V：ON 选项启动 cmd （激活延迟扩展，否则关闭默认），但这是不实际的。
 
 
 
如何修改 PATH 变量的方式我在上面描述过，并且在调用脚本后，在我当前的DOS会话中仍然有更新
解决方案
页面 提供了一个函数如何在DOS中返回值的很好的例子，即使使用模式：
 
 
 
以下函数将使用添加 PATH 更新所需的任何变量：
 ：cleanAddPath  - 从％〜1中删除％〜2，将其添加到％〜1 
的结尾SETLOCAL ENABLEDELAYEDEXPANSION 
设置P =！％〜1！ 
设置P =！P：％〜2 =！ 
设置P =！P：;; =;！ 
设置P =！P！;％〜2 
设置P =！P：;; = 
（ENDLOCAL& REM .-- RETURN VALUES 
 SET％〜1 =％P％
）
退出/ b 
  
注意使用的路径的并置。作为 ：
  SET％〜1 =％P％是允许记住（使用％〜1 表示的变量）您使用延迟扩展功能设置的值。
 
我最初使用 SET％〜1 =％P％！，但 ：
要更新您的 PATH 变量，您可以调用您的功能与：
 调用：cleanAddPath PATHC：\my\path\to\add
  
在离开该脚本后，将持续存在您当前的DOS会话。
 
 
 
 的指出一个更强大的答案（upvoted），但在我的情况下，这个脚本就够了。
 
Context: I need to call a Windows batch script which would update my PATH by adding another path 'xxx' at the end of it, but:
without any duplicate
(if I add 'xxx' to a PATH like 'aaa;xxx;bbb', I need an updated PATH like 'aaa;bbb;xxx')
without any aggregation
(I can call the script repeatedly without ending up with 'aaa;bbb;xxx;xxx;xxx;...')
What I have tried:
The following function takes care of any duplicate and does the job
:cleanAddPath -- remove %~1 from PATH, add it at the end of PATH
SETLOCAL ENABLEDELAYEDEXPANSION
set PATH=!PATH:%~2=!
set PATH=!PATH:;;=;!
set PATH=%PATH%;%~2
set P=!P:;;=;!
echo %PATH%
echo -------------
ENDLOCAL
exit /b
But, it needs delayed expansion local mode, which means: at the end of the script (or here, at the end of the function cleanAddPath), whatever has been set for %PATH% is thrown away.
I could ask the users (for which I write the script) to launch their cmd with a cmd /V:ON option (activating the delayed expansion, otherwise off by default), but that is not practical.
How can I modify the PATH variable the way I described above, and still have it updated in my current DOS session after calling said script?
 解决方案 
The page "DOS - Function Collection" gives great example on how a function can return a value in DOS, even when using delayed expansion mode:
The following function will update any variable you want with an addition PATH:
:cleanAddPath -- remove %~2 from %~1, add it at the end of %~1
SETLOCAL ENABLEDELAYEDEXPANSION
set P=!%~1!
set P=!P:%~2=!
set P=!P:;;=;!
set P=!P!;%~2
set P=!P:;;=;!
(ENDLOCAL & REM.-- RETURN VALUES
  SET "%~1=%P%"
)
exit /b
Note the concatenation of paths using. As jeb comments:
The SET "%~1=%P%" is the part which allows to memorize (in the variable represented by %~1) the value you have set using delayed expansion features.
I initially used  SET "%~1=%P%" !, but jeb comments:
To update your PATH variable, you would call your function with:
call :cleanAddPath PATH "C:\my\path\to\add"
And it will persists after leaving that script, for your current DOS session.
dbenham's answer points to a more robust answer (upvoted), but in my case this script is enough.
                        
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