Twig: added path() function, exposed app and this in templates

docs/view_renderers.md

@@ -18,6 +18,7 @@ array(
 				),
 				'twig' => array(
 					'class' => 'yii\renderers\TwigViewRenderer',
+					'twigPath' => '@app/vendors/Twig',
 				),
 				// ...
 			),
@@ -38,6 +39,21 @@ or `$this->renderPartial()` from your controller:
 echo $this->render('renderer.twig', array('username' => 'Alex'));
 ```
 
+### Additional functions
+
+Additionally to regular Twig syntax the following is available in Yii:
+
+```php
+<a href="{{ path('blog/view', {'alias' : post.alias}) }}">{{ post.title }}</a>
+```
+
+path function calls `Html::url()` internally.
+
+### Additional variables
+
+- `app` = `\Yii::$app`
+- `this` = current `View` object
+
 Smarty
 ------
 

framework/renderers/TwigViewRenderer.php

@@ -12,6 +12,7 @@ namespace yii\renderers;
 use Yii;
 use yii\base\View;
 use yii\base\ViewRenderer;
+use yii\helpers\Html;
 
 /**
  * TwigViewRenderer allows you to use Twig templates in views.
@@ -53,6 +54,12 @@ class TwigViewRenderer extends ViewRenderer
 		$this->twig = new \Twig_Environment($loader, array_merge(array(
 			'cache' => Yii::getAlias($this->cachePath),
 		), $this->options));
+
+		$this->twig->addFunction('path', new \Twig_Function_Function(function($path, $args = array()){
+			return Html::url(array_merge(array($path), $args));
+		}));
+
+		$this->twig->addGlobal('app', \Yii::$app);
 	}
 
 	/**
@@ -69,6 +76,7 @@ class TwigViewRenderer extends ViewRenderer
 	 */
 	public function render($view, $file, $params)
 	{
+		$this->twig->addGlobal('this', $view);
 		return $this->twig->render(file_get_contents($file), $params);
 	}
 }