How can I create a menu items from meta box based on users input

Question

I have created a metabox that takes a name that the user can give as an additional name of their post. I am wondering how I can automatically create a menu item based on the name the user input into the metabox, and set the url to #PostName?

Even if someone could guide me in the right direction on creating the menu item from a metabox on the post screen I could figure out the rest.

EDIT: I have added some extra info since I understand it seems a little confusing to someone who has know idea of why I want this.

I am creating a custom theme with the html5 boilerplate. It is a one page theme that users add sections to the page by adding posts. The theory is the user adds a custom name to the post into a meta box on the page and it will add the menu item with that name. Since the meta box I created already adds an ID in the html of each post with an additional ID tag the url for the menu will be #PostName. This is so when the user clicks the menu item it will automatically scroll right to the section.

In most themes the Nav menu brings you to a different page. Since my theme is only a one page theme the nav links will bring the user to the section on the page. All I am trying to accomplish is to add some automation in the theme so the users don't need to add the menu items manually.

Answer 1

Here's how I understand this task: get posts (you can shape this any way you want by adding extra parameters to the query), for each post get its meta-box value (replace the key with yours), if value found add it to the menu's HTML.

Note: code is not tested, it is more of an outline.

$html = '';
$domain = 'your-domain'; // http://codex.wordpress.org/Function_Reference/_e
$meta_key = 'your-meta-key'; // TODO replace value with yours

$post_menu_items = get_posts( array(
    'post_type'     =>  'post',
    'post_status'   =>  array( 'publish' ),
    'numberposts'   =>  -1
) );

if($post_menu_items){
    $html .= '<ul>';
    foreach ($post_menu_items as $key => $menu_item) {
        $meta_title = get_post_meta($menu_item->ID, $meta_key, true);
        if(!empty($current_meta)){
            $html .='<li><a href="#' . $meta_title . '">' . $menu_item->post_title . '</a></li>';
        }
    }
    $html = '</ul>';
} else {
    _e('No posts found.', $domain);
}
echo $html;

Thinking about it, you could even avoid the get_post_meta call by supplying a meta_key parameter into your get_posts. You're welcome to experiment with that.