Twig で symfony のヘルパー関数を超強引に使えるようにする Extension (HelperTokenParser はもっと簡単に書けた。後で直す）

HelperTwigExtension.php

<?php

class HelperTwigExtension extends Twig_Extension
{
  static protected $helpers = array();

  public function getTokenParsers()
  {
    if (empty(self::$helpers))
    {
      self::$helpers = $this->generateHelperList();
    }

    $parsers = array();
    foreach (self::$helpers as $helper)
    {
      $parsers[] = new HelperTokenParser($helper);
    }

    return $parsers;
  }

  public function generateHelperList()
  {
    $result = array();

    $funcs = get_defined_functions();
    foreach ($funcs['user'] as $func)
    {
      $reflection = new ReflectionFunction($func);
      if (strpos($reflection->getFileName(), 'helper'))
      {
        $result[] = $func;
      }
    }

    return $result;
  }

  public function getName()
  {
    return 'helper';
  }
}

class HelperTokenParser extends Twig_TokenParser
{
  protected $name = '';

  public function __construct($name)
  {
    $this->name = $name;
  }

  public function parse(Twig_Token $token)
  {
    $allowed = array(Twig_Token::NAME_TYPE, Twig_Token::NUMBER_TYPE, Twig_Token::STRING_TYPE);
    $values = array();

    while (true)
    {
      $stream = $this->parser->getStream()->next();
      if ($stream->getType() === Twig_Token::BLOCK_END_TYPE)
      {
        break;
      }

      if (!in_array($stream->getType(), $allowed))
      {
        continue;
      }

      $values[] = $stream->getValue();
    }

    return new HelperNode($this->getTag(), $values);
  }

  public function getTag()
  {
    return $this->name;
  }
}

class HelperNode extends Twig_Node
{
  protected $name, $values;

  public function __construct($name, $values)
  {
    $this->name = $name;
    $this->values = $values;
  }

  public function compile($compiler)
  {
    $compiler->write('echo call_user_func_array("'.$this->name.'", ')
      ->repr($this->values)
      ->write(');');
  }
}