Permalink Shortcode

This must exist somewhere in WordPress or as part of a plugin, so if you know what plugin I should have used, feel free to heap on the abuse in the comments section. Anyway...

I wanted a way to create a link to a WP page from inside a post or page that wouldn't need modification when the target page's parent was changed. WordPress's permalink scheme uses a hierarchy of parent/child/grandchild/ to identify pages, and this can change as a page is reparented. If the parenting scheme is meant to represent a navigational hieararchy, you could have dead links.

I ended up with this function, loosely based on snippets I found on the web:
function permalink_func( $atts, $content=null ) {
extract( shortcode_atts( array(
'p' => '1',
), $atts ) );
if ($content == null)
$content = get_the_title($p);
$link = get_permalink($p);

return "$content";
}
add_shortcode( 'prm', 'permalink_func' );
(It lives in functions.php inside a php block.)

The short code is used like this: [prm p=1] or [prm p=6]link title[/prm]. If the short code is used with no closing tag, the article's title is used to label the link. The parameter (p=17) is the ID of the page, and can be seen by mousing over the page or post in the admin interface. The URL generated by the shortcode matches the current permalink scheme.

Once again, I am amazed by how easy it is to get things done with WordPress. It doesn't seem right...