added a Twig extension to create Expression instances

src/Symfony/Bridge/Twig/Extension/ExpressionExtension.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\Extension;
+
+use Symfony\Component\ExpressionLanguage\Expression;
+
+/**
+ * ExpressionExtension gives a way to create Expressions from a template.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ExpressionExtension extends \Twig_Extension
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getFunctions()
+    {
+        return array(
+            new \Twig_SimpleFunction('expression', array($this, 'createExpression')),
+        );
+    }
+
+    private function createExpression($expression)
+    {
+        return new Expression($expression);
+    }
+
+    /**
+     * Returns the name of the extension.
+     *
+     * @return string The extension name
+     */
+    public function getName()
+    {
+        return 'expression';
+    }
+}

src/Symfony/Bundle/TwigBundle/Resources/config/twig.xml

@@ -19,6 +19,7 @@
         <parameter key="twig.extension.form.class">Symfony\Bridge\Twig\Extension\FormExtension</parameter>
         <parameter key="twig.extension.httpkernel.class">Symfony\Bridge\Twig\Extension\HttpKernelExtension</parameter>
         <parameter key="twig.extension.debug.stopwatch.class">Symfony\Bridge\Twig\Extension\StopwatchExtension</parameter>
+        <parameter key="twig.extension.expression.class">Symfony\Bridge\Twig\Extension\ExpressionExtension</parameter>
         <parameter key="twig.form.engine.class">Symfony\Bridge\Twig\Form\TwigRendererEngine</parameter>
         <parameter key="twig.form.renderer.class">Symfony\Bridge\Twig\Form\TwigRenderer</parameter>
         <parameter key="twig.translation.extractor.class">Symfony\Bridge\Twig\Translation\TwigExtractor</parameter>
@@ -92,6 +93,10 @@
             <argument type="service" id="debug.stopwatch" on-invalid="ignore" />
         </service>
 
+        <service id="twig.extension.expression" class="%twig.extension.expression.class%" public="false">
+            <tag name="twig.extension" />
+        </service>
+
         <service id="twig.extension.httpkernel" class="%twig.extension.httpkernel.class%" public="false">
             <argument type="service" id="fragment.handler" />
         </service>