in reply to Re^3: Unshift and push inside of map operation. (test)
in thread Unshift and push inside of map operation.

However, my testing on Perl 5.8.8 and 5.10 shows that shift @empty returns a single undef, not an empty list
This is actually the documented behaviour, not (just) a quirk of implementation: shift.

In Section Seekers of Perl Wisdom