#! /usr/bin/env perl

use strict;
use warnings;

use feature 'say';
use DDP;
use YAML::XS qw/ DumpFile LoadFile /;

my $file = './aoa.yaml';

if ( -e $file ) {
  my $data = LoadFile($file);
  p $data;
}
else {
  my $data = [ [ 1 .. 3 ], [ 4 .. 6 ] ];
  DumpFile($file, $data);
  say "Look at $file...";
}