There different shades of pointless in this discussion. :)

you don't have to keep all $arefs after construction.

  DB<112> for $aref ( [1,2,3],[4,5,6],[7,8,9] ) { 
                      $lookup{$aref} = $aref; 
                      $hash{$aref}   = [ reverse @$aref ]; 
                      }
 => ""

  DB<113> \%hash
 => {
  "ARRAY(0xa547e40)" => [9, 8, 7],
  "ARRAY(0xa5c2e68)" => [6, 5, 4],
  "ARRAY(0xa5c3188)" => [3, 2, 1],
}

  DB<114> \%lookup
 => {
  "ARRAY(0xa547e40)" => [7, 8, 9],
  "ARRAY(0xa5c2e68)" => [4, 5, 6],
  "ARRAY(0xa5c3188)" => [1, 2, 3],
}

  DB<115> print "@{$lookup{$_}}\n" for keys %hash
7 8 9
4 5 6
1 2 3

[download]

Hiding all of this behind a tied hash should be feasible, (depending on implementation details of Tie::Hash , IAW when, where and how "stringization" happens )

Anyway I didn't try to find such implementations on CPAN.

One use case could be to implement sets of complex data structures including set operations

Cheers Rolf

( addicted to the Perl Programming Language)

updates
corrected link to Tie::Hash

In reply to Re^3: Allocation of anonymous arrays by LanX
in thread Allocation of anonymous arrays by OwlHoot

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