With caching (so it runs fast for large numbers), with variables, and not generating warnings/errors if strict and/or warnings were to be turned on: 
{@::cache = (0, 1)}
sub fib {
    {push @::n, shift}
    {return pop @::n if $::n[-1] < 2}
    {$::cache [$::n[-1]] ||= fib ($::n[-1] - 1) + fib ($::n[-1] - 2)}
    {return $::cache[pop @::n]}
}

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In reply to Re: Programming in Perl without semicolon by JavaFan
in thread Programming in Perl without semicolon by buetow

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