How do you access Tie::IxHash keys?

Question

Greetings I need to generate a xml document from a nested perl hash, keeping the order of the hash keys. I am trying out https://metacpan.org/pod/Tie::IxHash for the keeping the keys in order part. However I cannot figure out how to access the hash keys that Tie::IxHash creates, they dont behave like a hash key, hash ref key or an object. In the sample code I create a Tie::IxHash and try to print the key Transmitter Here is the sample code:

use strict;
use warnings;

use diagnostics;
use Scalar::Util;
use Data::Dumper;
use XML::Writer;
use Tie::IxHash;
use DateTime::Format::XSD;

my $time = time;


my $dt = DateTime->now;
my $timestamp = DateTime::Format::XSD->format_datetime($dt);
my $transmissionId = sprintf("%u",int(rand(100000000000000000000))). "E";


#sample data structure as hsah ref
# my $transmissionHeader = {
#       TransmissionId => "$transmissionId",
#       Timestamp => "$timestamp",
#       Transmitter => {
#           ETIN => '1232456789',
#               SOME => '5555555555',
#       }
#   };
    

my $transmissionHeader  = Tie::IxHash->new(
        TransmissionId => "$transmissionId",
        Timestamp => "$timestamp",
        Transmitter => Tie::IxHash->new( #each nested hash a new object?
            ETIN => '1232456789',
            SOME => '5555555555',
                                                                ),
    );
        
print Dumper $transmissionHeader;

# tried all these no joy
print "$transmissionHeader{Transmitter} \n";
print "$transmissionHeader->{Transmitter} \n";
print "$transmissionHeader->Transmitter() \n";

Answer 1

You can use the Indices() method to get the index of the key, and then use the Values() method to get the value of that key:

my $idx = $transmissionHeader->Indices('Transmitter');
my $hash = $transmissionHeader->Values($idx);
print Dumper $hash;