<?php
class PHPArray implements ArrayAccess {
  private $array = array();

  public function offsetExists($offset) {
    return array_key_exists($this->array, $offset);
  }

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

  public function offsetSet($offset, $value) {
    if (is_null($offset)) {
      $this->array[] = $value;
    } else {
      $this->array[$offset] = $value;
    }
  }

  public function offsetUnset($offset) {
    unset($this->array[$offset]);
  }
}

$test = new PHPArray;

$test[] = 'Hello'; $test[] = ' World!';
print $test[0] . $test[1];
?>