diff --git a/NEW_FEATURES.txt b/NEW_FEATURES.txt
index b2c18c99b..d08c830fd 100644
--- a/NEW_FEATURES.txt
+++ b/NEW_FEATURES.txt
@@ -2,6 +2,20 @@
 
 This file contains a brief description of new features which have been added to Smarty 3.1
 
+Smarty 3.1.28
+
+    Filter support
+    ==============
+    Optional filter names
+      An optional filter name was added to $smarty->registerFilter(). It can be used to unregister a filter by name.
+      - $smarty->registerFilter('output', $callback, 'name');
+        $smarty->unregister('output', 'name');
+
+    Closures
+      $smarty->registerFilter() does now accept closures.
+      - $smarty->registerFilter('pre', function($source) {return $source;});
+      If no optional filter name was specified it gets the default name 'closure'.
+
 Smarty 3.1.22
 
     Namespace support within templates
diff --git a/change_log.txt b/change_log.txt
index 5606b1d83..575f3133e 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -1,13 +1,17 @@
- ===== 3.1.27===== (18.06.2015)
-18.06.2015
- - bugfix another update on file path normalization failed on path containing something like "/.foo/" https://github.com/smarty-php/smarty/issues/56
+ ===== 3.1.28-dev===== (xx.xx.2015)
+ 19.06.2015
+  - improvement allow closures as callback at $smarty->registerFilter() https://github.com/smarty-php/smarty/issues/59
+
+ ===== 3.1.27===== (18.06.2015)
+ 18.06.2015
+  - bugfix another update on file path normalization failed on path containing something like "/.foo/" https://github.com/smarty-php/smarty/issues/56
 
  ===== 3.1.26===== (18.06.2015)
-18.06.2015
- - bugfix file path normalization failed on path containing something like "/.foo/" https://github.com/smarty-php/smarty/issues/56
+ 18.06.2015
+  - bugfix file path normalization failed on path containing something like "/.foo/" https://github.com/smarty-php/smarty/issues/56
 
-17.06.2015
- - bugfix calling a plugin with nocache option but no other attributes like {foo nocache} caused call to undefined function https://github.com/smarty-php/smarty/issues/55
+ 17.06.2015
+  - bugfix calling a plugin with nocache option but no other attributes like {foo nocache} caused call to undefined function https://github.com/smarty-php/smarty/issues/55
 
  ===== 3.1.25===== (15.06.2015)
  15.06.2015
diff --git a/libs/Smarty.class.php b/libs/Smarty.class.php
index 1f0f2634a..791546bb7 100644
--- a/libs/Smarty.class.php
+++ b/libs/Smarty.class.php
@@ -27,7 +27,7 @@
  * @author    Uwe Tews
  * @author    Rodney Rehm
  * @package   Smarty
- * @version   3.1.27
+ * @version   3.1.28-dev
  */
 
 /**
@@ -111,7 +111,7 @@ class Smarty extends Smarty_Internal_TemplateBase
     /**
      * smarty version
      */
-    const SMARTY_VERSION = '3.1.27';
+    const SMARTY_VERSION = '3.1.28-dev/1';
 
     /**
      * define variable scopes
diff --git a/libs/sysplugins/smarty_internal_extension_filter.php b/libs/sysplugins/smarty_internal_extension_filter.php
new file mode 100644
index 000000000..1fd8fcaf4
--- /dev/null
+++ b/libs/sysplugins/smarty_internal_extension_filter.php
@@ -0,0 +1,150 @@
+<?php
+
+/**
+ * Smarty Extension Filter
+ *
+ * Register filter methods
+ * Load filter method
+ *
+ * @package    Smarty
+ * @subpackage PluginsInternal
+ * @author     Uwe Tews
+ */
+class Smarty_Internal_Extension_Filter
+{
+    /**
+     * Valid filter types
+     *
+     * @var array
+     */
+    static $filterTypes = array('pre' => true, 'post' => true, 'output' => true, 'variable' => true);
+
+    /**
+     * Registers a filter function
+     *
+     * @param  \Smarty_Internal_Template|\Smarty $obj
+     * @param  string                            $type filter type
+     * @param  callback                          $callback
+     * @param  string|null                       $name optional filter name
+     *
+     * @throws \SmartyException
+     */
+    static function registerFilter($obj, $type, $callback, $name)
+    {
+        self::_checkFilterType($type);
+        $name = isset($name) ? $name : self::_getFilterName($callback);
+        if (!is_callable($callback)) {
+            throw new SmartyException("{$type}filter \"{$name}\" not callable");
+        }
+        $smarty = isset($obj->smarty) ? $obj->smarty : $obj;
+        $smarty->registered_filters[$type][$name] = $callback;
+    }
+
+    /**
+     * Unregisters a filter function
+     *
+     * @param  \Smarty_Internal_Template|\Smarty $obj
+     * @param  string                            $type filter type
+     * @param  callback|string                   $callback
+     *
+     */
+    static function unregisterFilter($obj, $type, $callback)
+    {
+        self::_checkFilterType($type);
+        $smarty = isset($obj->smarty) ? $obj->smarty : $obj;
+        if (isset($smarty->registered_filters[$type])) {
+            $name = is_string($callback) ? $callback : self::_getFilterName($callback);
+            if (isset($smarty->registered_filters[$type][$name])) {
+                unset($smarty->registered_filters[$type][$name]);
+                if (empty($smarty->registered_filters[$type])) {
+                    unset($smarty->registered_filters[$type]);
+                }
+            }
+        }
+    }
+
+    /**
+     * load a filter of specified type and name
+     *
+     * @param  \Smarty_Internal_Template|\Smarty $obj
+     * @param  string                            $type filter type
+     * @param  string                            $name filter name
+     *
+     * @return bool
+     * @throws SmartyException if filter could not be loaded
+     */
+    static function loadFilter($obj, $type, $name)
+    {
+        self::_checkFilterType($type);
+        $smarty = isset($obj->smarty) ? $obj->smarty : $obj;
+        $_plugin = "smarty_{$type}filter_{$name}";
+        $_filter_name = $_plugin;
+        if ($smarty->loadPlugin($_plugin)) {
+            if (class_exists($_plugin, false)) {
+                $_plugin = array($_plugin, 'execute');
+            }
+            if (is_callable($_plugin)) {
+                $smarty->registered_filters[$type][$_filter_name] = $_plugin;
+                return true;
+            }
+        }
+        throw new SmartyException("{$type}filter \"{$name}\" not callable");
+    }
+
+    /**
+     * unload a filter of specified type and name
+     *
+     * @param  \Smarty_Internal_Template|\Smarty $obj
+     * @param  string                            $type filter type
+     * @param  string                            $name filter name
+     *
+     */
+    static function unloadFilter($obj, $type, $name)
+    {
+        self::_checkFilterType($type);
+        $smarty = isset($obj->smarty) ? $obj->smarty : $obj;
+        if (isset($smarty->registered_filters[$type])) {
+            $_filter_name = "smarty_{$type}filter_{$name}";
+            if (isset($smarty->registered_filters[$type][$_filter_name])) {
+                unset ($smarty->registered_filters[$type][$_filter_name]);
+                if (empty($smarty->registered_filters[$type])) {
+                    unset($smarty->registered_filters[$type]);
+                }
+            }
+        }
+    }
+
+    /**
+     * Return internal filter name
+     *
+     * @param  callback $function_name
+     *
+     * @return string   internal filter name
+     */
+    static function _getFilterName($function_name)
+    {
+        if (is_array($function_name)) {
+            $_class_name = (is_object($function_name[0]) ? get_class($function_name[0]) : $function_name[0]);
+
+            return $_class_name . '_' . $function_name[1];
+        } elseif (is_string($function_name)) {
+            return $function_name;
+        } else {
+            return 'closure';
+        }
+    }
+
+    /**
+     * Check if filter type is valid
+     *
+     * @param string $type
+     *
+     * @throws \SmartyException
+     */
+    static function _checkFilterType($type)
+    {
+        if (!isset(self::$filterTypes[$type])) {
+            throw new SmartyException("Illegal filter type \"{$type}\"");
+        }
+    }
+}
\ No newline at end of file
diff --git a/libs/sysplugins/smarty_internal_filter_handler.php b/libs/sysplugins/smarty_internal_filter_handler.php
index 4f0f3981c..754f924f9 100644
--- a/libs/sysplugins/smarty_internal_filter_handler.php
+++ b/libs/sysplugins/smarty_internal_filter_handler.php
@@ -43,22 +43,21 @@ public static function runFilter($type, $content, Smarty_Internal_Template $temp
                         $output = $plugin_name($output, $template);
                     } elseif (class_exists($plugin_name, false)) {
                         // loaded class of filter plugin
+                        if (!is_callable(array($plugin_name, 'execute'))) {
+                            throw new SmartyException("Auto load {$type}-filter plugin method \"{$plugin_name}::execute\" not callable");
+                        }
                         $output = call_user_func(array($plugin_name, 'execute'), $output, $template);
                     }
                 } else {
                     // nothing found, throw exception
-                    throw new SmartyException("Unable to load filter {$plugin_name}");
+                    throw new SmartyException("Unable to auto load {$type}-filter plugin \"{$plugin_name}\"");
                 }
             }
         }
         // loop over registerd filters of specified type
         if (!empty($template->smarty->registered_filters[$type])) {
             foreach ($template->smarty->registered_filters[$type] as $key => $name) {
-                if (is_array($template->smarty->registered_filters[$type][$key])) {
                     $output = call_user_func($template->smarty->registered_filters[$type][$key], $output, $template);
-                } else {
-                    $output = $template->smarty->registered_filters[$type][$key]($output, $template);
-                }
             }
         }
         // return filtered output
diff --git a/libs/sysplugins/smarty_internal_templatebase.php b/libs/sysplugins/smarty_internal_templatebase.php
index 68fd4be2e..8fab99be4 100644
--- a/libs/sysplugins/smarty_internal_templatebase.php
+++ b/libs/sysplugins/smarty_internal_templatebase.php
@@ -23,6 +23,7 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
      * @var string
      */
     public $cache_id = null;
+
     /**
      * Set this if you want different sets of compiled files for the same
      * templates.
@@ -30,12 +31,14 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
      * @var string
      */
     public $compile_id = null;
+
     /**
      * caching enabled
      *
      * @var boolean
      */
     public $caching = false;
+
     /**
      * cache lifetime in seconds
      *
@@ -46,7 +49,7 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
     /**
      * test if cache is valid
      *
-     * @param  string|object $template   the resource handle of the template file or template object
+     * @param  string|\Smarty_Internal_Template $template   the resource handle of the template file or template object
      * @param  mixed         $cache_id   cache id to be used with this template
      * @param  mixed         $compile_id compile id to be used with this template
      * @param  object        $parent     next higher level of Smarty variables
@@ -121,7 +124,7 @@ public function getTemplateId($template_name, $cache_id = null, $compile_id = nu
      * @param  string   $type       plugin type
      * @param  string   $tag        name of template tag
      * @param  callback $callback   PHP callback to register
-     * @param  boolean  $cacheable  if true (default) this fuction is cachable
+     * @param  boolean  $cacheable  if true (default) this function is cache able
      * @param  array    $cache_attr caching attributes if any
      *
      * @return Smarty_Internal_Templatebase current Smarty_Internal_Templatebase (or Smarty or
@@ -174,7 +177,8 @@ public function unregisterPlugin($type, $tag)
     public function registerResource($type, $callback)
     {
         $smarty = isset($this->smarty) ? $this->smarty : $this;
-        $smarty->registered_resources[$type] = $callback instanceof Smarty_Resource ? $callback : array($callback, false);
+        $smarty->registered_resources[$type] = $callback instanceof Smarty_Resource ? $callback : array($callback,
+            false);
 
         return $this;
     }
@@ -265,8 +269,8 @@ public function registerObject($object_name, $object_impl, $allowed = array(), $
         }
         // register the object
         $smarty = isset($this->smarty) ? $this->smarty : $this;
-        $smarty->registered_objects[$object_name] =
-            array($object_impl, (array) $allowed, (boolean) $smarty_args, (array) $block_methods);
+        $smarty->registered_objects[$object_name] = array($object_impl, (array) $allowed, (boolean) $smarty_args,
+            (array) $block_methods);
 
         return $this;
     }
@@ -387,83 +391,47 @@ public function registerDefaultConfigHandler($callback)
     /**
      * Registers a filter function
      *
-     * @param  string   $type filter type
-     * @param  callback $callback
+     * @param  string     $type filter type
+     * @param  callback   $callback
+     * @param null|string $name option filter name
      *
-     * @return Smarty_Internal_Templatebase current Smarty_Internal_Templatebase (or Smarty or
+     * @return \Smarty_Internal_TemplateBase current Smarty_Internal_Templatebase (or Smarty or
      *                                      Smarty_Internal_Template) instance for chaining
+     * @throws \SmartyException
      */
-    public function registerFilter($type, $callback)
+    public function registerFilter($type, $callback, $name = null)
     {
-        $smarty = isset($this->smarty) ? $this->smarty : $this;
-        $smarty->registered_filters[$type][$this->_get_filter_name($callback)] = $callback;
-
+        Smarty_Internal_Extension_Filter::registerFilter($this, $type, $callback, $name);
         return $this;
     }
 
     /**
      * Unregisters a filter function
      *
-     * @param  string   $type filter type
-     * @param  callback $callback
+     * @param  string          $type filter type
+     * @param  callback|string $callback
      *
      * @return Smarty_Internal_Templatebase current Smarty_Internal_Templatebase (or Smarty or
      *                                      Smarty_Internal_Template) instance for chaining
      */
     public function unregisterFilter($type, $callback)
     {
-        $name = $this->_get_filter_name($callback);
-        $smarty = isset($this->smarty) ? $this->smarty : $this;
-        if (isset($smarty->registered_filters[$type][$name])) {
-            unset($smarty->registered_filters[$type][$name]);
-        }
-
+        Smarty_Internal_Extension_Filter::unregisterFilter($this, $type, $callback);
         return $this;
     }
 
-    /**
-     * Return internal filter name
-     *
-     * @param  callback $function_name
-     *
-     * @return string   internal filter name
-     */
-    public function _get_filter_name($function_name)
-    {
-        if (is_array($function_name)) {
-            $_class_name = (is_object($function_name[0]) ?
-                get_class($function_name[0]) : $function_name[0]);
-
-            return $_class_name . '_' . $function_name[1];
-        } else {
-            return $function_name;
-        }
-    }
-
     /**
      * load a filter of specified type and name
      *
      * @param  string $type filter type
      * @param  string $name filter name
      *
+     * @return bool
      * @throws SmartyException if filter could not be loaded
      */
     public function loadFilter($type, $name)
     {
-        $smarty = isset($this->smarty) ? $this->smarty : $this;
-        $_plugin = "smarty_{$type}filter_{$name}";
-        $_filter_name = $_plugin;
-        if ($smarty->loadPlugin($_plugin)) {
-            if (class_exists($_plugin, false)) {
-                $_plugin = array($_plugin, 'execute');
-            }
-            if (is_callable($_plugin)) {
-                $smarty->registered_filters[$type][$_filter_name] = $_plugin;
-
-                return true;
-            }
-        }
-        throw new SmartyException("{$type}filter \"{$name}\" not callable");
+        return Smarty_Internal_Extension_Filter::loadFilter($this, $type, $name);
     }
 
     /**
@@ -477,12 +445,7 @@ public function loadFilter($type, $name)
      */
     public function unloadFilter($type, $name)
     {
-        $smarty = isset($this->smarty) ? $this->smarty : $this;
-        $_filter_name = "smarty_{$type}filter_{$name}";
-        if (isset($smarty->registered_filters[$type][$_filter_name])) {
-            unset ($smarty->registered_filters[$type][$_filter_name]);
-        }
-
+        Smarty_Internal_Extension_Filter::unloadFilter($this, $type, $name);
         return $this;
     }
 
@@ -491,7 +454,7 @@ public function unloadFilter($type, $name)
      *
      * @param  string $match match string
      *
-     * @return string replacemant
+     * @return string replacement
      */
     private function replaceCamelcase($match)
     {