Yes, built-in since Perl 5.20, released mid 2014. use experimental qw(signatures); sub plus_one($x = 100) { return $x + 1; } # Says 6. say pl

Yes, built-in since Perl 5.20, released mid 2014. use experimental qw(signatures); sub plus_one($x = 100) { return $x + 1; } # Says 6. say plus_one(5); # Says 101. say plus_one(); (The subroutine signatures feature is still marked experimental, which is a shame. I use it in virtually all my code, unless I want pre-5.20 compatibility.)