#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

{   package Array::Apply;
    use Moose::Role;

    before install_accessors => sub {
        my $class  = shift;
        my $name   = $class->name;
        my $method = "apply_to_$name";
        $class->associated_class->add_method(
            $method => sub {
                my ($self, $code) = @_;
                $_ = $code->($_) for @{ $self->$name };
            }
        );
    };
}

{   package My;
    use Moose;

    has list => ( is      => 'rw',
                  isa     => 'ArrayRef[Str]',
                  default => sub { [] },
                  traits  => [qw[ Array Array::Apply ]],
                  handles => {
                      add_to_list   => 'push',
                      list_elements => 'elements',
                  },
    );
    __PACKAGE__->meta->make_immutable;
}

my $obj = My->new;
$obj->add_to_list(qw( a b c ));
$obj->apply_to_list(sub { uc });
say for $obj->list_elements;