Simple XML Encoder

simplexmlencoder.php

<?php
function simple_xml_encoder($data, $rootNode = 'response', $node = 'string') {
    function traverse($data, $node) {
        $xml = '';
        if (is_array($data) || is_object($data)) {
            foreach ($data as $key => $value) {
                if (is_numeric($key)) {
                    $key = $node;
                }
                if (empty($value)) {
                    $format = '<%1$s />';
                }
                else {
                    $format = '<%1$s>%2$s</%1$s>';
                }
                $xml .= sprintf($format, $key, traverse($value, $node));
            }
        } else {
            $xml = htmlspecialchars($data, ENT_QUOTES);
        }
        return $xml;
    }

    $nodes = traverse($data, $node);
    $format = '<%1$s>%2$s</%1$s>';
    $xml = sprintf($format, $rootNode, $nodes);
    return $xml;
}