Perhaps my favorite parts of Perl 6 are subroutine signatures and getting rid of "
my $self = shift;".
These features available now in Perl 5, without source filters, using Method::Signatures.
Sure, it's labeled as "ALPHA" involves some dark magic to make it work, but it's there to play with. And if it can be hacked up as a module, surely it would be feasible to add to Perl 5.12....