The point of Double Negation is casting any true value to 1, and any false value to 0.

See also: Re^2: Secret Perl Operators: The Highlander List Asserter

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

In reply to Re: The mystery of double negation by shmem
in thread The mystery of double bitwise negation by hurricup

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