Wordpress shortcode function for creating a breadcrumb

wp-breadcrumb.php

<?php

/**
 * Get breadcrumb from current page
 * 
 * usage   : [my_breadcrumb]
 * returns : HTML String 
 */
function my_breadcrumb_func() {
    global $post;
    $string = '';

    $ancestors = array_merge(
        array(get_option('page_on_front')), 
        array_reverse($post->ancestors), 
        array($post->ID)
    );
    foreach ($ancestors as $key => $ancestor) {
        $string .= ($key > 0) ? '<span class="marker">&raquo;</span>' : '';
        $string .= '<a href="'.get_permalink($ancestor).'">'.get_the_title($ancestor).'</a>';
    }

    return '<p class="breadcrumb">'.$string.'</p>';
}
add_shortcode('my_breadcrumb', 'my_breadcrumb_func');