Add a Class to Current Page WP_LINK_PAGES

I’ve noticed WordPress has some illogical differences between wp_link_pages and paginate_links. Specifically, WP_LINK_PAGES does not automatically add a class to the current page like paginate_links does.

Anybody have a quick functions fix?

This is what I use as a replacement for wp_link_pages(). Instead of a separate class it uses another element for the current page, because a page should never link to the current URL.

/**
 * Modification of wp_link_pages() with an extra element to highlight the current page.
 *
 * @param  array $args
 * @return void
 */
function t5_numerical_link_pages( $args = array () )
{
    $defaults = array(
        'before'      => '<p>' . __( 'Pages:', 't5_theme' )
    ,   'after'       => '</p>'
    ,   'link_before' => ''
    ,   'link_after'  => ''
    ,   'pagelink'    => '%'
    ,   'echo'        => 1
    // element for the current page
    ,   'highlight'   => 'b'
    );

    $r = wp_parse_args( $args, $defaults );
    $r = apply_filters( 'wp_link_pages_args', $r );
    extract( $r, EXTR_SKIP );

    global $page, $numpages, $multipage, $more, $pagenow;

    if ( ! $multipage )
    {
        return;
    }

    $output = $before;

    for ( $i = 1; $i < ( $numpages + 1 ); $i++ )
    {
        $j       = str_replace( '%', $i, $pagelink );
        $output .= ' ';

        if ( $i != $page || ( ! $more && 1 == $page ) )
        {
            $output .= _wp_link_page( $i ) . "{$link_before}{$j}{$link_after}</a>";
        }
        else
        {   // highlight the current page
            // not sure if we need $link_before and $link_after
            $output .= "<$highlight>{$link_before}{$j}{$link_after}</$highlight>";
        }
    }

    $echo and print $output . $after;
    return $output . $after;
}