#! /usr/bin/env perl
use strict;
use warnings;

use Storable qw(dclone);

my $max_foo = 4;
my $max_bar = 3;;

my @_bar2 = map {
    {
      x => undef,
      y => undef,
      foo => [ map { { a => undef, b => undef, s => undef } } 1 .. $max_foo ]
    }
} 1 .. $max_bar;

require Data::Dumper;
print Data::Dumper->new( [ \@_bar2 ], [ "*_bar" ] )->Sortkeys(1)->Dump();