diff -r 6d109e3804ac -r 9a001a04b634 Twig-1.3.0/lib/Twig/NodeVisitor/Optimizer.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Twig-1.3.0/lib/Twig/NodeVisitor/Optimizer.php	Tue Oct 25 23:56:28 2011 +0200
@@ -0,0 +1,203 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) 2010 Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Twig_NodeVisitor_Optimizer tries to optimizes the AST.
+ *
+ * This visitor is always the last registered one.
+ *
+ * You can configure which optimizations you want to activate via the
+ * optimizer mode.
+ *
+ * @package twig
+ * @author  Fabien Potencier <fabien@symfony.com>
+ */
+class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface
+{
+    const OPTIMIZE_ALL         = -1;
+    const OPTIMIZE_NONE        = 0;
+    const OPTIMIZE_FOR         = 2;
+    const OPTIMIZE_RAW_FILTER  = 4;
+
+    protected $loops = array();
+    protected $optimizers;
+
+    /**
+     * Constructor.
+     *
+     * @param integer $optimizers The optimizer mode
+     */
+    public function __construct($optimizers = -1)
+    {
+        if (!is_int($optimizers) || $optimizers > 2) {
+            throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));
+        }
+
+        $this->optimizers = $optimizers;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
+            $this->enterOptimizeFor($node, $env);
+        }
+
+        return $node;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if (self::OPTIMIZE_FOR === (self::OPTIMIZE_FOR & $this->optimizers)) {
+            $this->leaveOptimizeFor($node, $env);
+        }
+
+        if (self::OPTIMIZE_RAW_FILTER === (self::OPTIMIZE_RAW_FILTER & $this->optimizers)) {
+            $node = $this->optimizeRawFilter($node, $env);
+        }
+
+        $node = $this->optimizePrintNode($node, $env);
+
+        return $node;
+    }
+
+    /**
+     * Optimizes print nodes.
+     *
+     * It replaces:
+     *
+     *   * "echo $this->render(Parent)Block()" with "$this->display(Parent)Block()"
+     *   * "echo $this->getContext('...')" with "if (isset('...')) { echo '...' }"
+     *
+     * @param Twig_NodeInterface $node A Node
+     * @param Twig_Environment   $env  The current Twig environment
+     */
+    protected function optimizePrintNode($node, $env)
+    {
+        if (!$node instanceof Twig_Node_Print) {
+            return $node;
+        }
+
+        if (
+            $node->getNode('expr') instanceof Twig_Node_Expression_BlockReference ||
+            $node->getNode('expr') instanceof Twig_Node_Expression_Parent ||
+            ($node->getNode('expr') instanceof Twig_Node_Expression_Name && !$env->hasExtension('sandbox') && !$env->isStrictVariables())
+        ) {
+            $node->getNode('expr')->setAttribute('output', true);
+
+            return $node->getNode('expr');
+        }
+
+        return $node;
+    }
+
+    /**
+     * Removes "raw" filters.
+     *
+     * @param Twig_NodeInterface $node A Node
+     * @param Twig_Environment   $env  The current Twig environment
+     */
+    protected function optimizeRawFilter($node, $env)
+    {
+        if ($node instanceof Twig_Node_Expression_Filter && 'raw' == $node->getNode('filter')->getAttribute('value')) {
+            return $node->getNode('node');
+        }
+
+        return $node;
+    }
+
+    /**
+     * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
+     *
+     * @param Twig_NodeInterface $node A Node
+     * @param Twig_Environment   $env  The current Twig environment
+     */
+    protected function enterOptimizeFor($node, $env)
+    {
+        if ($node instanceof Twig_Node_For) {
+            // disable the loop variable by default
+            $node->setAttribute('with_loop', false);
+            array_unshift($this->loops, $node);
+        } elseif (!$this->loops) {
+            // we are outside a loop
+            return;
+        }
+
+        // when do we need to add the loop variable back?
+
+        // the loop variable is referenced for the current loop
+        elseif ($node instanceof Twig_Node_Expression_Name && 'loop' === $node->getAttribute('name')) {
+            $this->addLoopToCurrent();
+        }
+
+        // block reference
+        elseif ($node instanceof Twig_Node_BlockReference || $node instanceof Twig_Node_Expression_BlockReference) {
+            $this->addLoopToCurrent();
+        }
+
+        // include without the only attribute
+        elseif ($node instanceof Twig_Node_Include && !$node->getAttribute('only')) {
+            $this->addLoopToAll();
+        }
+
+        // the loop variable is referenced via an attribute
+        elseif ($node instanceof Twig_Node_Expression_GetAttr
+            && (!$node->getNode('attribute') instanceof Twig_Node_Expression_Constant
+                || 'parent' === $node->getNode('attribute')->getAttribute('value')
+               )
+            && (true === $this->loops[0]->getAttribute('with_loop')
+                || ($node->getNode('node') instanceof Twig_Node_Expression_Name
+                    && 'loop' === $node->getNode('node')->getAttribute('name')
+                   )
+               )
+        ) {
+            $this->addLoopToAll();
+        }
+    }
+
+    /**
+     * Optimizes "for" tag by removing the "loop" variable creation whenever possible.
+     *
+     * @param Twig_NodeInterface $node A Node
+     * @param Twig_Environment   $env  The current Twig environment
+     */
+    protected function leaveOptimizeFor($node, $env)
+    {
+        if ($node instanceof Twig_Node_For) {
+            array_shift($this->loops);
+        }
+    }
+
+    protected function addLoopToCurrent()
+    {
+        $this->loops[0]->setAttribute('with_loop', true);
+    }
+
+    protected function addLoopToAll()
+    {
+        foreach ($this->loops as $loop) {
+            $loop->setAttribute('with_loop', true);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getPriority()
+    {
+        return 255;
+    }
+}