<?php

class Core_View_Type_Array implements ArrayAccess, Countable, IteratorAggregate {

    /* ... */

    protected $iterator = null;

    /* ... */

    public function getIterator($isNew = true) {
        if ($isNew || is_null($this->iterator)) {
            $this->iterator = new Core_View_Type_Array_Iterator(clone $this);
        }
        return $this->iterator;
    }

    /* ... */

}

class Core_View_Type_Array_Iterator implements Iterator {

    protected $array;
    protected $keys;
    protected $current;
    protected $length;

    public function __construct(ArrayAccess $array) {
        $this->array = $array;
        $this->keys = $this->array->keys();
        $this->length = $this->array->count();
        $this->rewind();
    }

    public function current() {
        return $this->array->offsetGet($this->keys[$this->current]);
    }

    public function key() {
        return $this->keys[$this->current];
    }

    public function next() {
        $this->current++;
    }

    public function rewind() {
        $this->current = 0;
    }

    public function valid() {
        return $this->current < $this->length;
    }

    public function isFirst() {
        return $this->current == 0;
    }

    public function isLast() {
        return $this->current + 1 == $this->length;
    }

}