xfn_check( string $class, string $value = '', mixed $deprecated = '' )

function xfn_check( $class, $value = '', $deprecated = '' ) {
	global $link;

	if ( ! empty( $deprecated ) ) {
		_deprecated_argument( __FUNCTION__, 'WP-2.5.0' ); // Never implemented
	}

	$link_rel = isset( $link->link_rel ) ? $link->link_rel : ''; // In PHP 5.3: $link_rel = $link->link_rel ?: '';
	$rels = preg_split('/\s+/', $link_rel);

	if ('' != $value && in_array($value, $rels) ) {
		echo ' checked="checked"';
	}

	if ('' == $value) {
		if ('family' == $class && strpos($link_rel, 'child') === false && strpos($link_rel, 'parent') === false && strpos($link_rel, 'sibling') === false && strpos($link_rel, 'spouse') === false && strpos($link_rel, 'kin') === false) echo ' checked="checked"';
		if ('friendship' == $class && strpos($link_rel, 'friend') === false && strpos($link_rel, 'acquaintance') === false && strpos($link_rel, 'contact') === false) echo ' checked="checked"';
		if ('geographical' == $class && strpos($link_rel, 'co-resident') === false && strpos($link_rel, 'neighbor') === false) echo ' checked="checked"';
		if ('identity' == $class && in_array('me', $rels) ) echo ' checked="checked"';
	}
}