Re^2: eval, Read environment variable and expand using eval

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Re^3: eval, Read environment variable and expand using eval by ikegami (Patriarch) on Feb 19, 2010 at 07:03 UTC
You should be getting that since you're printing `$stmt`. You should also be getting the value of `$ENV{HOST}` or `sqlhost`.	[reply] [d/l] [select]
Re^4: eval, Read environment variable and expand using eval by cdarke (Prior) on Feb 19, 2010 at 09:27 UTC
Remember that an environment variable can be defined yet empty. In sh: `MYVAR=` [download] In perl: `$ENV{MYVAR} = "";` [download]	[reply] [d/l] [select]
Re^3: eval, Read environment variable and expand using eval by bot403 (Beadle) on Feb 19, 2010 at 14:58 UTC
There is a subtle yet important difference between defined and exists on hash and array elements. Defined will autovivify your hash element and make its value undefined. Perhaps you meant this? `$r = (exists $ENV{INFORMIXSQLHOSTS}) ? $ENV{INFORMIXSQLHOSTS} : 'sqlho +st')` [download] If you want to check every possiblity this would be the best. However I usually just do the exists() check. `$r = ((exists $ENV{INFORMIXSQLHOSTS} && defined($ENV{INFORMIXSQLHOSTS} +) && length($ENV{INFORMIXSQLHOSTS}) ) ? $ENV{INFORMIXSQLHOSTS} : 's +qlhost'));` [download]	[reply] [d/l] [select]
Re^4: eval, Read environment variable and expand using eval by Anonymous Monk on Feb 19, 2010 at 15:04 UTC
No, defined does not autovivify `my %f; warn snot => defined $f{snot}; warn snot => exists $f{snot}; __END__ snot at - line 3. snot at - line 4.` [download]	[reply] [d/l]
Re^5: eval, Read environment variable and expand using eval by bot403 (Beadle) on Feb 19, 2010 at 17:08 UTC
Darnit. I thought defined() autovivified simple hashes. Both exists and defined still can autovivify on deep hashes though. `#!/usr/bin/perl # use warnings; use Data::Dumper; my $h = { 'foo' => 1 }; if(exists($h->{notexist}{baz})){ } if(defined($h->{notdefined}{baz})){ } print Dumper($h); exit 0;` [download] `$VAR1 = { 'notexist' => {}, 'foo' => 1, 'notdefined' => {} };` [download]	[reply] [d/l] [select]
Re^6: eval, Read environment variable and expand using eval by ikegami (Patriarch) on Feb 19, 2010 at 21:29 UTC
Re^6: eval, Read environment variable and expand using eval by Anonymous Monk on Feb 19, 2010 at 17:36 UTC