Hi wtc,

Have been debating whether to post this or not. Was playing with this code while we were discussing your issue when a couple of people suggested using Tie::IxHash, but then found its ordering wasn't recognized by YAML::XS. Here it is for whatever it may be worth.

In an earlier post a quote from the YAML Spec shows the proper format for ordered mappings. Below is code to recursively convert a data structure containing IxHash's to one needed for output by YAML::XS. There is also a function to recursively convert a structure loaded from YAML::XS into one containing properly ordered IxHash's.

The code is presented as is, i'm sure there is a more elegant and less bug ridden version trying to get out -- would be happy to receive criticism. Mostly I hope it helps with your problem if you're still looking for a solution

use strict;
use warnings;

use Tie::IxHash;
use Data::Dumper;
use Data::Rmap qw(:types rmap_to);

sub ixhash_to_yamlxs
{
    my $item = \+shift;
    my $get_yaml_struct = sub {
        my $raw = shift;
        my $ix = tied(%$raw);
        return $raw unless defined $ix and $ix->isa('Tie::IxHash');
        return [ map { { $_ => $raw->{$_} } } $ix->Keys ];
    };
    rmap_to { $_ = $get_yaml_struct->($_) } HASH, $item;
    return $item;
}

sub yamlxs_to_ixhash
{
    my $item = shift;
    my $make_ixhash_from_array = sub {
        my $raw = shift;
        tie my(%hash), 'Tie::IxHash';
        eval {
            no warnings;
            for (@$raw) {
                return $raw if scalar keys $_ ne 1;
                my ($key) = keys $_;
                $hash{$key} = $_->{$key};
            }
        };
        return $raw if $@;
        return \%hash;
    };
    rmap_to { $_ = $make_ixhash_from_array->($_)  } ARRAY, \$item;
    return $item;
}

tie my(%embed), 'Tie::IxHash', (j => 5, k => 6, l => 7);
tie my(%hash), 'Tie::IxHash', (a => 1, c => { z => 26 }, b => 2, d => 
+[ 'j', 'k', 'l'], e => \%embed);

my $out = ixhash_to_yamlxs \%hash;
print Dumper $out;

my $in =  yamlxs_to_ixhash $out;
print Dumper $in;
[download]

# IxHash converted for output by YAML::XS
# Notice the embeded IxHash was handled
# and also an embeded native hash (key 'c')
# that is not converted to ordered structure
\[
    { 'a' => 1 },
    { 'c' => { 'z' => 26 } },
    { 'b' => 2 },
    { 'd' => [ 'j', 'k', 'l' ] },
    { 'e' => [ { 'j' => 5 },
           { 'k' => 6 },
           { 'l' => 7 }
         ]
    }
];
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# ordered Tie::IxHash recovered from YAML::XS format
\{
    'a' => 1,
    'c' => { 'z' => 26 },
    'b' => 2,
    'd' => [ 'j', 'k', 'l' ],
    'e' => {
         'j' => 5,
         'k' => 6,
         'l' => 7
       }
};
[download]