Oneindig diep afdalen

id	naam			cat
===================================
1	Gratis			 0
2	Niet gratis		 0
3	Shooters		 1
4	Shooters		 2
5	Strategie		 2
6	First-person		 4
7	Third-person		 4
8	Overige			 4
9	RPG			 2
10	RPG			 1

id	naam			cat
===================================
1	Gratis			 0
2	Niet gratis		 0
3	Shooters		 1
4	Shooters		 2
5	Strategie		 2
6	First-person		 4
7	Third-person		 4
8	Overige			 4
9	RPG			 2
10	RPG			 1

| ID | NAME | LEFT | RIGHT |
|--------------------------|
 1 --- Top --- 0 ---- 9
 2 --- Lala --- 1 --- 2
 3 --- oho --- 3 --- 8
 4 --- sub --- 4 --- 7
 5 --- subsub  5 --- 6

Structuur : 
Top
 |-- Lala
 |-- Oho
 |--|-- sub
 |--|--|-- subsub

| ID | NAME | LEFT | RIGHT |
|--------------------------|
 1 --- Top --- 0 ---- 9
 2 --- Lala --- 1 --- 2
 3 --- oho --- 3 --- 8
 4 --- sub --- 4 --- 7
 5 --- subsub  5 --- 6
 
Structuur : 
Top
 |-- Lala
 |-- Oho
 |--|-- sub
 |--|--|-- subsub

function print_option($wat, $level=0, &$tpl) {
	if(($level == 0 && is_array($wat)) || $level != 0) {
		if(is_array($wat)) {
			$level++;
			foreach($wat as $v) {
				print_option($v,$level,$tpl);
			}
		} else {
			$option = '<option value="'. $wat .'"';
			if((int)$_GET['id'] == $wat) {
				$option .= ' selected = "selected"';
			}
			$option .= '>'. str_repeat('-', ($level == 0) ? 0 : $level-1) . " ". get_category_titel($wat) .'</option>';
			$tpl->newblock('categorien');
			$tpl->assign('option', $option);
		}
	}
}

/* en deze hoort er bij om de categorie op te halen, dat zie je natuurlijk zelf maar */
function get_category_titel($id) {
	if(is_numeric($id)) {
		$titel = mysql_query("SELECT titel FROM categorien WHERE id = ". $id);
		if(mysql_num_rows($titel) > 0) {
			return mysql_result($titel, 0);
		} else {
			return 'geen titel';
		}
	}
	return 'geen titel';
}

function print_option($wat, $level=0, &$tpl) {
	if(($level == 0 && is_array($wat)) || $level != 0) {
		if(is_array($wat)) {
			$level++;
			foreach($wat as $v) {
				print_option($v,$level,$tpl);
			}
		} else {
			$option = '<option value="'. $wat .'"';
			if((int)$_GET['id'] == $wat) {
				$option .= ' selected = "selected"';
			}
			$option .= '>'. str_repeat('-', ($level == 0) ? 0 : $level-1) . " ". get_category_titel($wat) .'</option>';
			$tpl->newblock('categorien');
			$tpl->assign('option', $option);
		}
	}
}
 
/* en deze hoort er bij om de categorie op te halen, dat zie je natuurlijk zelf maar */
function get_category_titel($id) {
	if(is_numeric($id)) {
		$titel = mysql_query("SELECT titel FROM categorien WHERE id = ". $id);
		if(mysql_num_rows($titel) > 0) {
			return mysql_result($titel, 0);
		} else {
			return 'geen titel';
		}
	}
	return 'geen titel';
}