Defined.php

<?php

/*
 * This file is part of Twig.
 *
 * (c) 2011 Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Checks if a variable is defined in the current context.
 *
 * <pre>
 * {# defined works with variable names and variable attributes #}
 * {% if foo is defined %}
 *     {# ... #}
 * {% endif %}
 * </pre>
 *
 * @package twig
 * @author  Fabien Potencier <fabien@symfony.com>
 */
class Twig_Node_Expression_Test_Defined extends Twig_Node_Expression_Test {
  public function __construct(Twig_NodeInterface $node, $name, Twig_NodeInterface $arguments = null, $lineno) {
    parent::__construct($node, $name, $arguments, $lineno);
    if ($node instanceof Twig_Node_Expression_Name) {
      $node
        ->setAttribute('is_defined_test', true);
    }
    elseif ($node instanceof Twig_Node_Expression_GetAttr) {
      $node
        ->setAttribute('is_defined_test', true);
      $this
        ->changeIgnoreStrictCheck($node);
    }
    else {
      throw new Twig_Error_Syntax('The "defined" test only works with simple variables', $this
        ->getLine());
    }
  }
  protected function changeIgnoreStrictCheck(Twig_Node_Expression_GetAttr $node) {
    $node
      ->setAttribute('ignore_strict_check', true);
    if ($node
      ->getNode('node') instanceof Twig_Node_Expression_GetAttr) {
      $this
        ->changeIgnoreStrictCheck($node
        ->getNode('node'));
    }
  }
  public function compile(Twig_Compiler $compiler) {
    $compiler
      ->subcompile($this
      ->getNode('node'));
  }

}