protected function eachPageUncache($selector, callable $callback)
	{
		$num = 0;
		$id = 0;
		while (true) {
			$p = $this->pages->get("{$selector}, id>$id");
			if(!$id = $p->id) break;
			$callback($p);
			$this->pages->uncacheAll($p);
			$num++;
		}
		return $num;
	}
protected function eachPageUncache($selector, callable $callback)
	{
		$num = 0;
		$id = 0;
		while (true) {
			$p = $this->pages->get("{$selector}, id>$id");
			if(!$id = $p->id) break;
			$callback($p);
			$this->pages->uncacheAll($p);
			$num++;
		}
		return $num;
	}
protected function eachPageUncache ( $ selector , callable $ callback ) { $ num = 0 ; $ id = 0 ; while ( true ) { $ p = $ this -> pages -> get ( "{$selector}, id>$id" ) ; if ( ! $ id = $ p -> id ) break ; $ callback ( $ p ) ; $ this -> pages -> uncacheAll ( $ p ) ; $ num ++ ; } return $ num ; }
Cycle over a group of pages without running into memory exhaustion

@param string   $selector
@param callable $callback
@return int     $num
Cycle over a group of pages without running into memory exhaustion