Given this is a data structure design question, providing very specific broken code is not a good way of explaining what you want to do. 

my $x;
push @$x, [ [1,2] => 3 ];
my @xkeys = map $_->[0], @$x;
print $xkeys[0]->[0];

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In reply to Re: ArrayRef as Hash key by ikegami
in thread ArrayRef as Hash key by Anonymous Monk

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