Re^2: How to localize conditionally?

by ikegami (Patriarch)

on Mar 14, 2011 at 14:28 UTC ( [id://893095]=note: print w/replies, xml )

Need Help??

The library checks for existence, so that doesn't work. You'd need

local %ENV = condition ? (%ENV, BLAH=>42) : %ENV;
[download]

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Re^3: How to localize conditionally? (tias) by tye (Sage) on Mar 14, 2011 at 15:44 UTC
Did you test it? It works for me. - tye	[reply]
Re^4: How to localize conditionally? (tias) by ikegami (Patriarch) on Mar 14, 2011 at 16:07 UTC
No, but how can one assign to a hash element that does not exist? Well, %ENV is magical, so let's test it out. `$ perl -wE' my $condition = 0; say exists($ENV{BLAH}) \|\| 0; local $ENV{BLAH} = $condition ? 42 : $ENV{BLAH}; say exists($ENV{BLAH}) \|\| 0; ' 0 1` [download] So I was right `This is perl 5, version 12, subversion 2 (v5.12.2) built for i686-linu +x` [download]	[reply] [d/l] [select]
Re^5: How to localize conditionally? (tias) by tye (Sage) on Mar 14, 2011 at 16:18 UTC
My tests appeared to work for strange reasons. Sorry about that. But you can fix the original without copying the whole environment: `local $ENV{BLAH}; if( @ARGV ) { $ENV{BLAH}= 42; } else { delete $ENV{BLAH}; }` [download] - tye	[reply] [d/l]

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