in reply to Re^2: Can I do this ???
in thread Can I do this ???

Windows batch processing. 

@REM --------------------------------
@REM runme.cmd
@echo off
SET FOO=bar
echo %FOO%
echo Calling setter.cmd
call setter.cmd
echo After setter.cmd
echo %FOO%

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@REM ---------------------------------
@REM setter.cmd
echo "I am in setter."
set FOO=biz
echo Setters FOO = %FOO%

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--------------------------------------
output
--------------------------------------
bar
Calling setter.cmd
"I am in setter."
Setters FOO = biz
After setter.cmd
biz

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The called sub command, setter.cmd, resets the environment of the caller.

--MidLifeXis

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Re^4: Can I do this ???
by BrowserUk (Patriarch) on Jan 22, 2009 at 15:51 UTC

    The reason that works is because there is no child process involved.

    The called script is processed by the calling process--in the same fashion as Perl's do script.pl;--and the changes are made to the current process' environment by the current process.

    The effect is exactly the same as: 

    ## Called .pl
$::ENV{ somekey } = 'somevalue';

##calling script;
do 'called.pl';

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    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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      Very true, and I should have made that point clear.

      What I meant to demonstrate is that a "typical" windows batch mode programming style (well, what I saw when I was in an environment where I had to care about those scripts) allows, even encourages, modifying the "parent" process from things that are called.

      --MidLifeXis

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