Is this not what you need? 
$a=\$x;
$b=\$y;
print "$a $b\n"
($a,$b)=($b,$a);
print "$a $b\n";

[download]

update: changed $a and $b to references.

In reply to Re: How to swap scalar values without copies by asarih
in thread How to swap scalar values without copies by Anonymous Monk

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