Or the defined-or operator, more perl5.10ish ;-) 
$seen{$key} //= 1;
next;

[download]
print+qq(\L@{[ref\&@]}@{['@'x7^'!#2/"!4']});

In reply to Re^2: How good is gzip data as digest? by codeacrobat
in thread How good is gzip data as digest? by isync

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