class b implements Iterator
	{
		private $p	= 0;
		private $d	= [];
		
		function add($o1, $o2)
		{
			$this->d[] = [$o1, $o2];
		}
		
		function key()
		{
			return $this->d[$this->p][0];
		}
		
		function rewind()
		{
			$this->p = 0;
		}
		
		function current()
		{
			return $this->d[$this->p][1];
		}
		
		function next()
		{
			++$this->p;
		}
		
		
		function valid()
		{
			return isset($this->d[$this->p]);
		}
		
	}
	
	$b = new b;
	$b->add(new Str, new Str);
	
	
	foreach($b as $k => $v)
		var_dump($k); // object Str