Re: error message: Nesting level too deep - recursive dependency?

>class ListItem { > var $prev; > var $next; > var $data; > > function ListITem() { > $this->prev = NULL; > $this->next = NULL; > $this->data = NULL; > } >} Why can't you just use a PHP array?... >class List2 { > var $first; > var $last; > var $current; > var $length; > > function List2() > { > $this->first = NULL; > $this->last = NULL; > $this->current = NULL; > $this->length = 0; > } > > function Add(&$item) > { > if (is_null($this->first)) { > $item->prev = NULL; > $item->next = NULL; > $this->first = &$item; > $this->last = &$item; > } else { > $item->prev = &$this->last; > $item->next = NULL; > $item->prev->next = &$item; Not sure this twice-removed reference will work... Try this: $temp = &$this->last; $temp->next = &$item; > $this->last = &$item; > } > $this->length++; > } Ye Gods! You should *definitely* be using an array! :-) > function &item($index) > { > $i = 0; > > if ($index >= 0 && $index <= $this->length) { If $i == $this->length you should be returning NULL. Instead, you return $item for both $this->length - 1 and $this->length, I think... > $item = $this->first; > while ($index - $i > 0) { > $item = $item->next; > $i++; > } > } else $item = NULL; > > return $item; > } > > function findItem(&$item) > { > for ($i = 0;$i < $this->length;$i++) { > $current = $this->item($i); > > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! > !! Here is a problem !! > !! this comparation produced an error message !! > !! "Nesting level too deep - recursive dependency?" !! > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! > if($current == $item) return true; Well, the odds are really good that at some point you are hitting this situation: $current->next == $item $item->prev == $current When that happens, and you try to use == on $current and $item, PHP goes into a tail-spin trying to compare the two objects, since each refers to the other... In order to compare the two objects, it has to look inside ->next and ->prev, but they each refer to the other, so it looks inside them again, and has to look into ->prev and ->next and they refer to each other so it looks inside them again, and again, and again, and then it blows up eventually. Give every object a unique ID http://php.net/uniqid or something, and compare their IDs. > } > return false; > } >} It still boggles my mind that you'd want to even *do* all this when you have a built-in array type that can do everything you've done about a zillion times faster... -- Like Music? http://l-i-e.com/artists.htm