use warnings;
use strict;

my $t_bar = 1;
my $t_foo = 1 if $t_bar;

my $f_bar = 0;
my $f_foo = 1 if $f_bar;

print "true $t_foo false $f_foo";


#->true 1 false 
#->Use of uninitialized value in concatenation (.) or string ...
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Please forgive my ignorance, but what's wrong with it? $foo ends up as 1 when $bar is true and is undefined when $bar is false. Just as I expect it to be. (Active Perl 5.8.7)

Wrong. This piece of code is one of the weird things in perl, in this case, something that is sometimes used as a dirty trick, to create a static variable.

#!/usr/bin/perl -lw
print $];
for (1 .. 5) {
    my $i = 123 if $bar;
    print ++$i;
}
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Result:

Name "main::bar" used only once: possible typo at test.pl line 4.
5.008003
1
2
3
4
5
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Conclusion: Always assign something in a my declaration?

The following works as expected.

my $i = $bar ? 123 : undef;
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And yeah, that's really weird.


holli, /regexed monk/