Using template variables to determine a URL Format

UrlFormatsVariable.php

<?php
namespace Craft;

class UrlFormatsVariable
{
    // Use in the URL Format:
    // 
    //  {{ craft.urlFormats.treatments(object) }}
    public function treatments($entry)
    {
        // Craft checks the URL format with an array `object` first, to see if there's a {slug},
        // and so whether it should be checked for uniqueness and incremented if necessary.
        if (!$entry || !($entry instanceof EntryModel))
        {
            return '{slug}';
        }

        $isTreatment = ($entry->type->handle === 'treatment');
        $hasChildren = (bool) $entry->getChildren()->type(array('treatmentGroup', 'treatment'))->total();

        // If the entry has a parent, prepend it's URI, or just 'treatments'
        $parent = $entry->getParent();
        $uri    = ($parent) ? $parent->uri : Craft::t('treatments');

        // An Entry has it's own page if it isn't a treatment, or it has content, otherwise
        // it is displayed on the parent page, identified by 'path/to/parent#entry-slug'
        $uri .= ($hasChildren || !$isTreatment ? '/' : '#' );
        $uri .= $entry->slug;

        return $uri;
    }
}