sub invert {
    #234567890123456789012345678901234567
    join'',grep/[^\Q@_\E]/,map{chr}1..255
}

##</code><code>##

sub invert {
    #234567890123456789012345678901234567
    "@{[grep/[^\Q@_\E]/,map{chr}1..255]}"
}