You can view the source on GitHub.

Example setup:

$nav = new nav();
$nav->link_add('/', 'Home');
$nav->link_add('/contact/', 'Contact us');
$nav->link_add('/help/', 'Help');

And to print:

echo $nav->html();

Using groups

$nav = new nav();

$nav->group_add('Group A');
$nav->link_add('/a1/', 'A1');
$nav->link_add('/a2/', 'A2');
$nav->link_add('/a3/', 'A3');

$nav->group_add('Group B');
$nav->link_add('/b1/', 'B1');
$nav->link_add('/b2/', 'B2');
$nav->link_add('/b3/', 'B3');

$sub_nav = new nav();
$sub_nav->link_add('/about/1/', 'Page 1');
$sub_nav->link_add('/about/2/', 'Page 2');
$sub_nav->link_add('/about/3/', 'Page 3');

$nav = new nav();
$nav->link_add('/', 'Home');
$nav->link_add('/about/', 'About', array('child' => $sub_nav));

By default the sub-nav will not be rendered until the path matches the parent link.

To disable this behaviour you can call:

$nav->automatically_expand_children(false);

To have all sub-navs open:

$nav->expand_all_children(true);

Or just specify it on a per link basis:

$nav->link_add('/about/', 'About', array('child' => $sub_nav, 'open' => true));

Normally links will be selected automatically, based on the best match of request.uri.

Instead you can manually specify which link is selected:

$nav->link_add('/path/', 'Name', true);
$nav->link_add('/path/', 'Name', array('selected' => true));

Or to just switch off the automatic process, just call:

$nav->automatically_select_link(false);

Alternatively, if the 'request.uri' is not what you want to match against, you can instead call:

$nav->path_set('/path/');

Custom link text

If the navigation text needs to be set elsewhere (e.g. for localisation), then the nav object can be expended with

/app/library/class/nav.php

class nav extends nav_base {
    public function link_name_get($url)
    public function link_name_get($url, $config)
    public function link_name_get_html($url)
    public function link_name_get_html($url, $config)
}

An example of this is can be found for the basic-site.

White space

The whitespace indent can be set to something other than 3 tabs either by:

$nav->indent_set(3);

Or if you want to completely remove the white space:

$nav->include_white_space(false);

Other configuration

For the full list of link configuration options:

$nav->link_add('/about/', 'About', array(
        'selected' => true,
        'child' => $sub_nav,
        'open' => true,
        'html' => false, // If second parameter is already html encoded (e.g. an image)
        'item_class' => 'xxx',
        'link_class' => 'xxx',
        'link_title' => 'xxx',
    ));

Or if you just want to add a custom class to the main unordered list:

$nav->main_class_set('xxx');