my $dump = dumpf($data, sub {
    use List::Util qw/max/;
    my ($ctx, $obj) = @_;

    my %r;
    state %seen;

    if ('HASH' eq ref $obj and not $seen{$obj}++) {
        no warnings 'uninitialized'; # Unknown sort keys
        my $len = max map { length } keys $obj; # Keep results aligned
        my $sort_string =  'a' x max map { length } keys $obj;

        # Convert existing keys to ...aaaaa, ...aaaab, ...aaaac, etc.,
        # so Data::Dump's lexical sort works.
        my %keymap =  map { $sort_string++  => $_ }
                     sort { $num{$a} <=> $num{$b} } keys $obj;
        $obj->{$_} = delete $obj->{$keymap{$_}} for keys %keymap;

        my $dump = Data::Dump::dump($obj);

        # Replace to get original keys back
        $dump =~ s/$_/sprintf "%-${len}s",$keymap{$_}/e for keys %keymap;
        $r{dump} = $dump;
    }
    return \%r;
});
##</code><code>##

#!/usr/bin/env perl

use 5.012;
use warnings;

use Data::Dump qw/dump dumpf/;

# Sort numbers 'zero' through 'nine'
my %num;
@num{qw<one two three four five six seven eight nine>} = 1..9;

my $data = {
    two     => { qw<six inner eight works one the nine too seven hash> },
    one     => 'first',
    three   => 'third',
    unknown => 'unknown key',
};

dumpf($data, sub {
    use List::Util qw/max/;
    my ($ctx, $obj) = @_;

    my %r;
    state %seen;

    if ('HASH' eq ref $obj and not $seen{$obj}++) {
        no warnings 'uninitialized'; # Unknown sort keys
        my $len = max map { length } keys $obj; # Keep results aligned
        my $sort_string =  'a' x max map { length } keys $obj;

        # Convert existing keys to ...aaaaa, ...aaaab, ...aaaac, etc.,
        # so Data::Dump's lexical sort works.
        my %keymap =  map { $sort_string++  => $_ }
                     sort { $num{$a} <=> $num{$b} } keys $obj;
        $obj->{$_} = delete $obj->{$keymap{$_}} for keys %keymap;

        my $dump = Data::Dump::dump($obj);

        # Replace to get original keys back
        $dump =~ s/$_/sprintf "%-${len}s",$keymap{$_}/e for keys %keymap;
        $r{dump} = $dump;
    }
    return \%r;
});

##</code><code>##

{
  unknown => "unknown key",
  one     => "first",
  two     => {
               one   => "the",
               six   => "inner",
               seven => "hash",
               eight => "works",
               nine  => "too",
             },
  three   => "third",
}