$ 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'
PV(""\0)
PV("1"\0)
PV("123"\0)
PV("2"\0)
PV("\377"\0)
PV("\377"\0)
UNDEF