ChunkIterator.php

<?php
/**
 * Wraps an iterator allowing to obtain chunks of it as simple arrays
 *
 * It mimics the behaviour of the array_chunk() function.
 *
 * @license Public Domain
 * @author Iván -DrSlump- Montes <drslump_at_pollinimini_dot_net>
 */
class ChunkIterator implements Iterator, OuterIterator
{
    /** @var Traversable */
    protected $_it;
    /** @var Int */
    protected $_size;
    /** @var Int */
    protected $_count;
    /** @var array */
    protected $_current;
    /** @var bool */
    protected $_preserve;

    /**
     *
     * @param Iterator $it  The inner iterator or an array
     * @param Int $size The size of chunks
     * @param Bool $preserveKeys    If true preserves the original keys
     */
    public function __construct($it, $size, $preserveKeys = false)
    {
        if (is_array($it)) {
            $it = new ArrayIterator($it);
        }

        $this->_it = $it;
        $this->_size = $size;
        $this->_preserve = $preserveKeys;
        $this->_count = 0;
    }

    public function getInnerIterator()
    {
        return $this->_it;
    }

    public function rewind()
    {
        $this->_it->rewind();
        $this->_count = 0;
        $this->_current = null;

        $this->_consume();
    }

    public function current()
    {
        return $this->_current;
    }

    public function valid()
    {
        return count($this->_current) > 0;
    }

    public function key()
    {
        return $this->_count-1;
    }

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

    /**
     * Consume the inner iterator to fill up a chunk
     *
     */
    protected function _consume()
    {
        $this->_current = array();
        for ($i=0; $this->_it->valid() && $i<$this->_size; $i++) {
            $k = $this->_preserve ? $this->_it->key() : $i;
            $this->_current[$k] = $this->_it->current();
            $this->_it->next();
        }
        $this->_count++;
    }

}

Phptal_Chunk_Modifier.php

<?php

function phptal_tales_chunk($src, $nothrow)
{
    $parts = explode(' ', trim($src));
    $size = array_pop($parts);
    $src = implode(' ', $parts);
    return 'new ChunkIterator(' . phptal_tales($src, $nothrow) . ', ' . $size . ')';
}