...
$xml = XML::LibXML->new();
$data = $xml->parse_file($adr_indexfile);
$moteur = $data->getDocumentElement(); //element <moteur>
$mots = $moteur->getFirstChild(); //element <mots> qui contient des elements <motcle>
my $motcle = $data->createElement('motcle');
$motcle->setAttribute('nom', $mot);
$mots->appendChild($motcle);
my $url = $data->createElement('urls');
$motcle->appendChild($url);
my $lien = $data->createElement('lien');
$lien->setAttribute('valeururl', $ARGV[2]);
$url->appendChild($lien);
my $pond = $data->createElement('ponderation');
my $text = XML::LibXML::Text->new($ponderation);
$pond->appendChild($text);
 
print Dumper($data);

$VAR1 = bless( do{\(my $o = 148458496)}, 'XML::LibXML::document' );