use strict;
use XML::LibXML;
my %testHash;

## create a test hash
$testHash{root}{testEl1}{currentValue}      = 0;
$testHash{root}{testEl1}{comment}           = "System test element 1";
$testHash{root}{testEl1}{enable}            = 1;
$testHash{root}{testEl2}{currentValue}      = 0;
$testHash{root}{testEl2}{comment}           = "System test element 2";
$testHash{root}{testEl2}{enable}            = 1;
$testHash{root}{testEl2}{newLevel}{enable1} = 1;
$testHash{root}{testEl2}{newLevel}{enable2} = 1;
$testHash{root}{testEl2}{newLevel}{enable3} = 1;
$testHash{root}{testEl3}{newLevel}{enable}  = 1;

$testHash{root}{testEl2}{reference} = $testHash{root}{testEl1};

## call the hash processor!
my $string = myHash2Xml( \%testHash );

## create the output XML
open FILEOUT, ">myHash2Xml.xml";
print FILEOUT "$string\n";
close FILEOUT;

## end of script

## covert our hash to XML, this is a wrapper to create the
## document and pass it back as a string
sub myHash2Xml {
	my ($hash) = @_;

	## create a new xml document!
	my $xmlDoc = XML::LibXML::Document->new( '1.0', 'UTF-8' );

	## create the root element and a pointer to it!
	my $root = $xmlDoc->createElement("testDoc");
	$xmlDoc->setDocumentElement($root);

	examineHash( $hash, \$xmlDoc, \$root );    # process the hash

	my $xmlString = $xmlDoc->toString(1);
	print "$xmlString\n";

	return $xmlString;
}

## wrapper for the recurser,
sub examineHash {
	my ( $hash, $xmlDoc, $lastElement ) = @_;
	my %refsHash;                              # hash ref counter, used to prevent/detect circular refs
	examineHashRecurse( \%refsHash, $hash, $xmlDoc, $lastElement );    # here we go
}

## recurser!
sub examineHashRecurse {
	my ( $refsHash, $hash, $xmlDoc, $lastElement ) = @_;
	foreach my $key ( sort { $a cmp $b } keys( %{$hash} ) ) {          # go through keys at current level
		if ( ( $$hash{$key} . "" ) =~ /HASH\(/ ) {                     # is it another hash?
			## its another hash, go deeper!
			if ( !exists $$refsHash{ $$hash{$key} } ) {                # check if its in the reference hash
				$$refsHash{ $$hash{$key} } = 1;

				#				print "create element $key\n";
				my $newElement = $$xmlDoc->createElement($key);        # create new element
				$$lastElement->appendChild($newElement);               # add element to our doc under the last element

				## remember to pass the new element as a reference.
				examineHashRecurse( $refsHash, $$hash{$key}, $xmlDoc, \$newElement );
			}    ## else, this has alread been examined! stops circular continuation
			else {

				# do something with a circular reference???
				$$refsHash{ $$hash{$key} }++;
			}
		} else {

			#			print "create attribute $key with value " . $$hash{$key} . "\n";
			$$lastElement->setAttribute( "$key", $$hash{$key} );    # add attribute to the last element!
		}
	}
}