#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11152489
use warnings;

my @animals = (qw( cow camel dog cat  )); # slightly changed from 11150326
my @foods   = (qw( fish pasture meat  ));
my @places  = (qw( wood sea    desert ));
my $commands = {
    select => {
        completion_list => [@animals],
        commands => {
                        give => {
                                    completion_list => \@foods,
                        },
                        take_to => {
                                    completion_list => \@places,
                        },
        },
    },
    kill  => {
        completion_list => [@animals],
    }
};

use YAML qw( DumpFile LoadFile );
my $originalfile = 'original.11152489';
my $changedfile = 'changed.11152489';
DumpFile $originalfile, $commands;
$commands->{select}{commands}{give}{completion_list}[0] .= 'es';
DumpFile $changedfile, $commands;
system "diff -u $originalfile $changedfile";
use Data::Dump 'dd'; dd 'original', LoadFile $originalfile;
use Data::Dump 'dd'; dd 'changed',  LoadFile $changedfile;