whilst toying with some code, a friend and I came upon this:

use Data::Dumper qw/Dumper/;
my %a = map { $a{$_} => 1 unless undef, 0..5 } 0..11;
print Dumper \%a;
[download]

output:

$VAR = {
'11' => 12,
'1' => 2,
'3' => 4,
'7' => 8,
'9' => 10,
'5' => 6
};
[download]

same results if we change the 0..5 to 0..333 or 0..1, but doesn't work the same if we remove the range operator. We're confused here. we know it's screwy we're checking for it being undef in the assignment/map. the question is, where's that 12 coming from?

A second question, possibly related:

my %a = map { $a{ $a{ $a{ $a{ $a{ $_ } } } } } => 1, 0..5 } 0..9;
print Dumper sort(\%a);
[download]

also has the same output as:

my %a = map { $a{ $_ } => 1, 0..5 } 0..9;
[download]

why? these clearly aren't the same thing are they? am I missing something vital here?

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