use Data::Dumper;
$Data::Dumper::Purity=1;
use strict;
my $array=[0,1];
$array->[0]=\$array->[1];
$array->[1]=\$array->[0];
print Dumper($array);

[download]
Which outputs 
$VAR1 = [
          \\do{my $o},
          do{my $o}
        ];
${${$VAR1->[0]}} = $VAR1->[0];
$VAR1->[1] = ${$VAR1->[0]};

[download]
So whats wrong with the ouput?

In the original there are 3 variables involved.

$array, $array->[0] and $array->[1]

In the output there are 5 variables involved. In fact the ouput is syntactically equivelent to (and Dumper will ouput both arrays the same)

 my ($x,$y); $x=\$y; $y=\$x; my $array=[$x,$y];

Which of course contains 5 variables

$array, $array->[0], $array->[1], $x and $y

This can be verified by

$array->[1]='funky!'; print ${$array->[0]};

Which will print 'funky!' for the original input, but not for the ouput, nor for the second example.

<super>(code in one line to avoid CSS styles overriding the no-spoiler)</super>

<super>Highlight the above if you want the answer</super>

You didnt peek before answering did you?

;-)

Yves / DeMerphq
---
Writing a good benchmark isnt as easy as it might look.
<super>UPDATE:Forgot the Purity setting on first post.</super>

In reply to Puzzle: Whats wrong with Dumper by demerphq

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