Passing variables through permalink structure

I have a WordPress page which is accessible via /accommodation/.

What I want to be able to do is pass in a parameter using the URL – ie going to /accommodation/value1/ would load the same page as /accommodation/ – but still show the /accommodation/value1/ in the browser address bar.

I guess another way of putting it would be to say I need to be able to access /accommodation/ by adding anything I like to the end of the URL, whilst retaining the URL I entered in the browser window.

I’ve then got some code in the page template which does different things based on the values passed into the page.

Whilst I could use a query string, I want to avoid doing that so I can keep the “pretty URLs”.

Many thanks for any help / suggestions.

Solved it!

// Register the variables that will be used as parameters on the url
function add_my_var($public_query_vars) {
    $public_query_vars[] = 'extra_slug';
    return $public_query_vars;
}
add_filter('query_vars', 'add_my_var');

// Build the rewrite rules, for the extra parameter
function do_rewrite() {
    add_rewrite_rule('(accommodation)/[/]?([^/]*)$', 'index.php?pagename=accommodation&extra_slug=$matches[2]','top');
}
add_action('init', 'do_rewrite');

// The parameter is now accessible
get_query_var('extra_slug')