Get all "id" attributes from a data structure!

get_ids.pl

use strict;
use warnings;
use feature qw(say);

my $data = {
  'top' => {
    'window' => {
      'elements' => [
        { id =>  44, name => 'link', value => 'xyz' },
        { id =>  48, name => 'title', value => 'Home Page' },
        { id => 100, name => 'author', value => 'Admin' }
      ],
      id => 19
    },
    'cache' => [
      { id => 199, data => '9E27F645-2B37-46F3-B60C-36B1EFD235A2' },
      { id =>  40, data => 'F35FD610-A0AE-4C71-871D-6D19685D01A6' },
      { id => 100, data => { name => 'author', value => 'Admin' } }
    ],
    id => 55
  },
  id => 1
};

say join q( ), sort { $a <=> $b } get_ids( $data );

sub get_ids {
  my $ds = shift;
  return 'ARRAY' eq ref $ds ? ( map { get_ids( $_ ) } grep { ref $_ } @{$ds} )
       : 'HASH'  eq ref $ds ? ( map { ref $ds->{$_} ? get_ids($ds->{$_}) : $_ eq 'id' ? $ds->{$_} : () } keys %{$ds} )
       :                      ();
}