Node nid is a useful argument type

I'm suggesting adding an argument handler for node id. This enables a view to narrow itself down to a single node.

Why do that, you ask, when a list view could just as easily link to ?q=node/NID to show the node?

Well, in my case I'm building views with args that narrow the search first by taxonomy, then down to a single node. And I also have a navigation block that indicates where the user is browsing. So, if my user visits ?q=myview, then narrows to ?q=myview/4 (tid = 4) my navigation block builds a mock-menu to show them where they are. Finally the user picks a node. If the URL is ?q=myview/4/10 (nid=10) then my navigation block stays intact. But if the URL is ?q=node/10, my navigation block goes away.

Similarly, I could be defining a custom them for the node when browsing through myview, or I could handle the breadcrumbs differently.

So if you agree its useful, here's the code I'm using in my module:

function ocp_project_handler_arg_nid($op, &$query, $argtype, $arg = '') {
  switch($op) {
  case 'summary':
	$query->add_field("title");
  $query->add_field('nid');
	$fieldinfo['field'] = "node.nid";
    return $fieldinfo;
	break;
  case 'filter':
	$where = db_escape_string($arg);
    $query->add_where("node.nid = '$where'");
    break;
    case 'link':
	  $q = $_GET['q'];
      return l($query->title, "$q/".$query->nid);
    case 'title':
      return $query;
  }
}

The one part I really don't like is using $_GET['q'] to build the link. I'm open to suggestions there.