In the statement 
my $aap = \();

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perl is assigning to $app in scalar context. So the reference operator \ creates a reference for every element in the list, and returns the last element. Since there are no elements, this is a reference to undef. Consider 
my @a = (1,2,3);
my $b = 4;
my $aap = \(@a,$b);
print Dumper($aap);
my $aap = \($b,@a);
print Dumper($aap);
__OUTPUT__
$VAR1 = \4;
$VAR1 = [
          1,
          2,
          3
        ];

[download]
It is helpful to think of a list on the RHS as an initializer that can be evaluated in different contexts.

-Mark

In reply to Re: difference between \() and [] by kvale
in thread difference between \() and [] by eXile

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