Clean up the cruft on WP-generated menus

cleaner_menus.php

<?php
/**
 * De-cruft WordPress-generated menu HTML
 * @author Matt Wiebe
 * @link http://somadesign.ca/
 * @contributor Roger Johansson {@link} http://www.456bereastreet.com/archive/201101/cleaner_html_from_the_wordpress_wp_list_pages_function/
 * @license GPL v2 {@link} http://www.opensource.org/licenses/gpl-2.0.php
 * @copyright 2011
 */
class SD_Cleaner_Menus {

	private static $selected = 'current';
	private static $ancestor = 'ancestor';

	public static function init() {
		add_filter( 'wp_nav_menu', array(__CLASS__, 'cleanup' ) );
		add_action( 'wp_head', array(__CLASS__, 'add_permalink_filter'), 100 );
		add_filter( 'nav_menu_css_class', array(__CLASS__, 'filter_menu_classes'), 10, 2 );
	}

	// we add this late so as not to mess up canonical redirects
	public static function add_permalink_filter() {
		foreach ( array('post', 'page', 'term', 'post_type') as $type )
			add_filter( $type . '_link', array(__CLASS__, 'make_root_relative') );
	}

	public static function filter_menu_classes( $c, $item ) {
		$n = array();

		if ( in_array('current-menu-item', $c) ) {
			$n[] = self::$selected;
		}
		if ( in_array('current-page-ancestor', $c) ) {
			$n[] = self::$selected;
			$n[] = self::$ancestor;
		}
		// fix for root relative URLs
		if ( 'custom' === $item->type && 0 === strpos($item->url, '/') ) {
			if ( trailingslashit($item->url) === trailingslashit($_SERVER['REQUEST_URI']) ) {
				$n[] = self::$selected;
			}
		}

		return $n;
	}

	public static function cleanup( $menu = '' ) {
		if ( empty($menu) )
			return $menu;

		$menu = self::remove_ids($menu);
		$menu = self::remove_title_attributes($menu);
		$menu = self::remove_empty_classes($menu);

		return $menu;
	}

	private static function remove_ids($input) {
		return preg_replace('/\s*id\s*=\s*(["\']).*?\1/', '', $input);
	}

	private static function remove_title_attributes($input) {
		return preg_replace('/\s*title\s*=\s*(["\']).*?\1/', '', $input);
	}

	private static function remove_empty_classes($input) {
		return str_replace( array(' class=""', " class=''"), '', $input );
	}

	public static function make_root_relative( $input ) {
		return preg_replace('!http(s)?://' . $_SERVER['SERVER_NAME'] . '/!', '/', $input);
	}
}

SD_Cleaner_Menus::init();