class Twig_Node_Expression_Array

class Twig_Node_Expression_Array extends Twig_Node_Expression {
  protected $index;
  public function __construct(array $elements, $lineno) {
    parent::__construct($elements, array(), $lineno);
    $this->index = -1;
    foreach ($this
      ->getKeyValuePairs() as $pair) {
      if ($pair['key'] instanceof Twig_Node_Expression_Constant && ctype_digit((string) $pair['key']
        ->getAttribute('value')) && $pair['key']
        ->getAttribute('value') > $this->index) {
        $this->index = $pair['key']
          ->getAttribute('value');
      }
    }
  }
  public function getKeyValuePairs() {
    $pairs = array();
    foreach (array_chunk($this->nodes, 2) as $pair) {
      $pairs[] = array(
        'key' => $pair[0],
        'value' => $pair[1],
      );
    }
    return $pairs;
  }
  public function hasElement(Twig_Node_Expression $key) {
    foreach ($this
      ->getKeyValuePairs() as $pair) {

      // we compare the string representation of the keys
      // to avoid comparing the line numbers which are not relevant here.
      if ((string) $key == (string) $pair['key']) {
        return true;
      }
    }
    return false;
  }
  public function addElement(Twig_Node_Expression $value, Twig_Node_Expression $key = null) {
    if (null === $key) {
      $key = new Twig_Node_Expression_Constant(++$this->index, $value
        ->getLine());
    }
    array_push($this->nodes, $key, $value);
  }

  /**
   * Compiles the node to PHP.
   *
   * @param Twig_Compiler A Twig_Compiler instance
   */
  public function compile(Twig_Compiler $compiler) {
    $compiler
      ->raw('array(');
    $first = true;
    foreach ($this
      ->getKeyValuePairs() as $pair) {
      if (!$first) {
        $compiler
          ->raw(', ');
      }
      $first = false;
      $compiler
        ->subcompile($pair['key'])
        ->raw(' => ')
        ->subcompile($pair['value']);
    }
    $compiler
      ->raw(')');
  }

}