Perl v5.26 adds the experimental
declared_refs feature that expands on the experimental
refaliasing feature from v5.22. As with all experimental features, this may change or disappear according to perlpolicy.
refaliasing allows you to alias a named variable to a reference (even if that reference comes from a named variable). You could write that as either of these forms:
use v5.22; use feature qw(refaliasing); no warnings qw(experimental::refaliasing); \my @new = \@old; my @new; \@new = \@old;
In the first, you declared and assign in the same statement. The reference operator (
\) comes before the
my. In the second, you declare the new variable in one statement then alias in another.
declared_refs feature lets you move the reference operator to after the declarator (the
use v5.26; use feature qw(refaliasing declared_refs); no warnings qw(experimental::refaliasing declared_refs); my \@new = \@old;
This means that list assignments with a mix of ref aliasing and conventional assignments are now possible. This mix is not possible with just the v5.22 feature:
use feature qw(refaliasing declared_refs); no warnings qw(experimental::refaliasing experimental::declared_refs); my @cats = qw( Buster Ginger ); my %pets = ( 'Buster' => 'cat', 'Ginger' => 'cat', 'Addy' => 'dog', 'Nikki' => 'dog', ); my( $n, $m, \@y, \%z ) = ( 'Addy', 'Nikki', \@cats, \%pets );
This still doesn’t get you to ref aliasing in subroutine signatures but it’s a step closer to what you need for that.