$ perl -MDP -we'my@x=("",undef,"1","123","2","\xff","\x{00ff}");DPeek for map{$_->[1]}sort{$a->[0]cmp$b->[0]}map{[$_//"\x{1ffff}",$_]}@x'

Not sure what you're trying to prove with this. Do you think U+1ffff is the biggest Unicode character?

And chr(255) is *not* per definition an y with two dots.

Which is exactly why I said I was *hoping* it would get replaced with something less than 255. People around here need less sensitive nerd-rage triggers.