There's a current discussion on perl5porters about how /$x/ behaves specially when $x is empty (and this is true to /\Q$x/ as well). That magic is totally way crazyer than the one I'm using in this obfu (or the similar one in Re^3: A cleaner way of scoping variables; or the one you get if you combine either of these with inlined constant subroutines). My obfu is topped.