Implement linked list in php

If don't think most people understand what linked lists are. The basic idea is you want to keep data organised is such a way that you can access the previous and next node using the current node. The other features like add, delete, insert, head etc are sugar, though necessary. I think the SPL package does cover a lot. Problem is I need a PHP 5.2.9 class. Guess I've to implement it myself.

Just to clarify, implementing linked list in PHP using PHP arrays probably is not a good idea, because PHP array is hash-table under the hood (not simple low-level arrays). Simultaneously, you don't get advantages of pointers.

Instead, you can implement data structures like linked list for PHP using extensions, that means you are implementing a data structure in C to PHP.

Spl data structures are an example, another example is php-ds extension, specially in case of linked lists, you can use this: https://www.php.net/manual/en/class.ds-sequence.php

Sequence ADT is the unification of List ADT and Vector ADT, so you can use Sequence ADT implemented data structures as lists.

Hope this could help someone choose wisely.

// Here's a basic implementation of SplDoublyLinkedList using PHP.
$splDoubleLinkedList = new SplDoublyLinkedList();
$splDoubleLinkedList->push('a');
$splDoubleLinkedList->push('3');
$splDoubleLinkedList->push('v');
$splDoubleLinkedList->push('1');
$splDoubleLinkedList->push('p');
// $splDoubleLinkedList->unshift('10');
// $splDoubleLinkedList->pop();
$splDoubleLinkedList->add(3, 3.0);
// First of all, we need to rewind list.
$splDoubleLinkedList->rewind();
// Use while, check if the list has valid node.
while($splDoubleLinkedList->valid()){
  // Print current node's value.
   echo $splDoubleLinkedList->current()."\n";
 // Turn the cursor to next node.
 $splDoubleLinkedList->next();
}