Added Text extension with truncate filter.

Extension/Text.php

@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * This file is part of Twig.
+ *
+ * (c) 2009 Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @author Henrik Bjornskov <hb@peytz.dk>
+ * @package Twig
+ * @subpackage Twig-extensions
+ */
+class Twig_Extension_Text extends Twig_Extension
+{
+  /**
+   * Returns a list of filters.
+   *
+   * @return array
+   */
+  public function getFilters()
+  {
+    return array(
+      'truncate' => new Twig_Filter_Function('twig_truncate_filter', array('needs_environment' => true)),
+    );
+  }
+
+  /**
+   * Name of this extension
+   *
+   * @return string
+   */
+  public function getName()
+  {
+    return 'Text';
+  }
+}
+
+if (function_exists('mb_get_info'))
+{
+  function twig_truncate_filter(Twig_Environment $env, $value, $length = 30, $separator = '...')
+  {
+    if (mb_strlen($value, $env->getCharset()) > $length)
+    {
+      return mb_substr($value, 0, $length, $env->getCharset()).$separator;
+    }
+
+    return $value;
+  }
+}
+else
+{
+  function twig_truncate_filter(Twig_Environment $env, $value, $length = 30, $separator = '...')
+  {
+      if (strlen($value) > $length)
+      {
+        return substr($value, 0, $length).$separator;
+      }
+
+      return $value;
+  }
+}