class Twig_Parser

class Twig_Parser implements Twig_ParserInterface {
  protected $stack = array();
  protected $stream;
  protected $parent;
  protected $handlers;
  protected $visitors;
  protected $expressionParser;
  protected $blocks;
  protected $blockStack;
  protected $macros;
  protected $env;
  protected $reservedMacroNames;
  protected $importedFunctions;
  protected $tmpVarCount;
  protected $traits;
  protected $embeddedTemplates = array();

  /**
   * Constructor.
   *
   * @param Twig_Environment $env A Twig_Environment instance
   */
  public function __construct(Twig_Environment $env) {
    $this->env = $env;
  }
  public function getEnvironment() {
    return $this->env;
  }
  public function getVarName() {
    return sprintf('__internal_%s_%d', substr($this->env
      ->getTemplateClass($this->stream
      ->getFilename()), strlen($this->env
      ->getTemplateClassPrefix())), ++$this->tmpVarCount);
  }

  /**
   * Converts a token stream to a node tree.
   *
   * @param Twig_TokenStream $stream A token stream instance
   *
   * @return Twig_Node_Module A node tree
   */
  public function parse(Twig_TokenStream $stream, $test = null, $dropNeedle = false) {

    // push all variables into the stack to keep the current state of the parser
    $vars = get_object_vars($this);
    unset($vars['stack'], $vars['env'], $vars['handlers'], $vars['visitors'], $vars['expressionParser']);
    $this->stack[] = $vars;
    $this->tmpVarCount = 0;

    // tag handlers
    if (null === $this->handlers) {
      $this->handlers = $this->env
        ->getTokenParsers();
      $this->handlers
        ->setParser($this);
    }

    // node visitors
    if (null === $this->visitors) {
      $this->visitors = $this->env
        ->getNodeVisitors();
    }
    if (null === $this->expressionParser) {
      $this->expressionParser = new Twig_ExpressionParser($this, $this->env
        ->getUnaryOperators(), $this->env
        ->getBinaryOperators());
    }
    $this->stream = $stream;
    $this->parent = null;
    $this->blocks = array();
    $this->macros = array();
    $this->traits = array();
    $this->blockStack = array();
    $this->importedFunctions = array(
      array(),
    );
    $this->embeddedTemplates = array();
    try {
      $body = $this
        ->subparse($test, $dropNeedle);
      if (null !== $this->parent) {
        if (null === ($body = $this
          ->filterBodyNodes($body))) {
          $body = new Twig_Node();
        }
      }
    } catch (Twig_Error_Syntax $e) {
      if (null === $e
        ->getTemplateFile()) {
        $e
          ->setTemplateFile($this->stream
          ->getFilename());
      }
      throw $e;
    }
    $node = new Twig_Node_Module(new Twig_Node_Body(array(
      $body,
    )), $this->parent, new Twig_Node($this->blocks), new Twig_Node($this->macros), new Twig_Node($this->traits), $this->embeddedTemplates, $this->stream
      ->getFilename());
    $traverser = new Twig_NodeTraverser($this->env, $this->visitors);
    $node = $traverser
      ->traverse($node);

    // restore previous stack so previous parse() call can resume working
    foreach (array_pop($this->stack) as $key => $val) {
      $this->{$key} = $val;
    }
    return $node;
  }
  public function subparse($test, $dropNeedle = false) {
    $lineno = $this
      ->getCurrentToken()
      ->getLine();
    $rv = array();
    while (!$this->stream
      ->isEOF()) {
      switch ($this
        ->getCurrentToken()
        ->getType()) {
        case Twig_Token::TEXT_TYPE:
          $token = $this->stream
            ->next();
          $rv[] = new Twig_Node_Text($token
            ->getValue(), $token
            ->getLine());
          break;
        case Twig_Token::VAR_START_TYPE:
          $token = $this->stream
            ->next();
          $expr = $this->expressionParser
            ->parseExpression();
          $this->stream
            ->expect(Twig_Token::VAR_END_TYPE);
          $rv[] = new Twig_Node_Print($expr, $token
            ->getLine());
          break;
        case Twig_Token::BLOCK_START_TYPE:
          $this->stream
            ->next();
          $token = $this
            ->getCurrentToken();
          if ($token
            ->getType() !== Twig_Token::NAME_TYPE) {
            throw new Twig_Error_Syntax('A block must start with a tag name', $token
              ->getLine(), $this->stream
              ->getFilename());
          }
          if (null !== $test && call_user_func($test, $token)) {
            if ($dropNeedle) {
              $this->stream
                ->next();
            }
            if (1 === count($rv)) {
              return $rv[0];
            }
            return new Twig_Node($rv, array(), $lineno);
          }
          $subparser = $this->handlers
            ->getTokenParser($token
            ->getValue());
          if (null === $subparser) {
            if (null !== $test) {
              throw new Twig_Error_Syntax(sprintf('Unexpected tag name "%s" (expecting closing tag for the "%s" tag defined near line %s)', $token
                ->getValue(), $test[0]
                ->getTag(), $lineno), $token
                ->getLine(), $this->stream
                ->getFilename());
            }
            $message = sprintf('Unknown tag name "%s"', $token
              ->getValue());
            if ($alternatives = $this->env
              ->computeAlternatives($token
              ->getValue(), array_keys($this->env
              ->getTags()))) {
              $message = sprintf('%s. Did you mean "%s"', $message, implode('", "', $alternatives));
            }
            throw new Twig_Error_Syntax($message, $token
              ->getLine(), $this->stream
              ->getFilename());
          }
          $this->stream
            ->next();
          $node = $subparser
            ->parse($token);
          if (null !== $node) {
            $rv[] = $node;
          }
          break;
        default:
          throw new Twig_Error_Syntax('Lexer or parser ended up in unsupported state.', -1, $this->stream
            ->getFilename());
      }
    }
    if (1 === count($rv)) {
      return $rv[0];
    }
    return new Twig_Node($rv, array(), $lineno);
  }
  public function addHandler($name, $class) {
    $this->handlers[$name] = $class;
  }
  public function addNodeVisitor(Twig_NodeVisitorInterface $visitor) {
    $this->visitors[] = $visitor;
  }
  public function getBlockStack() {
    return $this->blockStack;
  }
  public function peekBlockStack() {
    return $this->blockStack[count($this->blockStack) - 1];
  }
  public function popBlockStack() {
    array_pop($this->blockStack);
  }
  public function pushBlockStack($name) {
    $this->blockStack[] = $name;
  }
  public function hasBlock($name) {
    return isset($this->blocks[$name]);
  }
  public function getBlock($name) {
    return $this->blocks[$name];
  }
  public function setBlock($name, $value) {
    $this->blocks[$name] = new Twig_Node_Body(array(
      $value,
    ), array(), $value
      ->getLine());
  }
  public function hasMacro($name) {
    return isset($this->macros[$name]);
  }
  public function setMacro($name, Twig_Node_Macro $node) {
    if (null === $this->reservedMacroNames) {
      $this->reservedMacroNames = array();
      $r = new ReflectionClass($this->env
        ->getBaseTemplateClass());
      foreach ($r
        ->getMethods() as $method) {
        $this->reservedMacroNames[] = $method
          ->getName();
      }
    }
    if (in_array($name, $this->reservedMacroNames)) {
      throw new Twig_Error_Syntax(sprintf('"%s" cannot be used as a macro name as it is a reserved keyword', $name), $node
        ->getLine());
    }
    $this->macros[$name] = $node;
  }
  public function addTrait($trait) {
    $this->traits[] = $trait;
  }
  public function hasTraits() {
    return count($this->traits) > 0;
  }
  public function embedTemplate(Twig_Node_Module $template) {
    $template
      ->setIndex(count($this->embeddedTemplates) + 1);
    $this->embeddedTemplates[] = $template;
  }
  public function addImportedFunction($alias, $name, Twig_Node_Expression $node) {
    $this->importedFunctions[0][$alias] = array(
      'name' => $name,
      'node' => $node,
    );
  }
  public function getImportedFunction($alias) {
    foreach ($this->importedFunctions as $functions) {
      if (isset($functions[$alias])) {
        return $functions[$alias];
      }
    }
  }
  public function isMainScope() {
    return 1 === count($this->importedFunctions);
  }
  public function pushLocalScope() {
    array_unshift($this->importedFunctions, array());
  }
  public function popLocalScope() {
    array_shift($this->importedFunctions);
  }

  /**
   * Gets the expression parser.
   *
   * @return Twig_ExpressionParser The expression parser
   */
  public function getExpressionParser() {
    return $this->expressionParser;
  }
  public function getParent() {
    return $this->parent;
  }
  public function setParent($parent) {
    $this->parent = $parent;
  }

  /**
   * Gets the token stream.
   *
   * @return Twig_TokenStream The token stream
   */
  public function getStream() {
    return $this->stream;
  }

  /**
   * Gets the current token.
   *
   * @return Twig_Token The current token
   */
  public function getCurrentToken() {
    return $this->stream
      ->getCurrent();
  }
  protected function filterBodyNodes(Twig_NodeInterface $node) {

    // check that the body does not contain non-empty output nodes
    if ($node instanceof Twig_Node_Text && !ctype_space($node
      ->getAttribute('data')) || !$node instanceof Twig_Node_Text && !$node instanceof Twig_Node_BlockReference && $node instanceof Twig_NodeOutputInterface) {
      if (false !== strpos((string) $node, chr(0xef) . chr(0xbb) . chr(0xbf))) {
        throw new Twig_Error_Syntax('A template that extends another one cannot have a body but a byte order mark (BOM) has been detected; it must be removed.', $node
          ->getLine(), $this->stream
          ->getFilename());
      }
      throw new Twig_Error_Syntax('A template that extends another one cannot have a body.', $node
        ->getLine(), $this->stream
        ->getFilename());
    }

    // bypass "set" nodes as they "capture" the output
    if ($node instanceof Twig_Node_Set) {
      return $node;
    }
    if ($node instanceof Twig_NodeOutputInterface) {
      return;
    }
    foreach ($node as $k => $n) {
      if (null !== $n && null === ($n = $this
        ->filterBodyNodes($n))) {
        $node
          ->removeNode($k);
      }
    }
    return $node;
  }

}