code: def listing(parser, token):
      
      var_name, parameters = listing_parse(token.split_contents())
      return ListingNode(var_name, parameters)
docs: Tag that will obtain listing of top objects for a given category and store them in context under given name.
  
      Usage::
  
          {% listing <limit>[ from <offset>][of <app.model>[, <app.model>[, ...]]][ for <category> ] [with children|descendents] [using listing_handler] as <result> %}
  
      Parameters:
          ==================================  ================================================
          Option                              Description
          ==================================  ================================================
          ``limit``                           Number of objects to retrieve.
          ``offset``                          Starting with number (1-based), starts from first
                                              if no offset specified.
          ``app.model``, ...                  List of allowed models, all if omitted.
          ``category``                        Category of the listing, all categories if not
                                              specified. Can be either string (tree path),
                                              or variable containing a Category object.
          ``children``                        Include items from direct subcategories.
          ``descendents``                     Include items from all descend subcategories.
          ``exclude``                         Variable including a ``Publishable`` to omit.
          ``using``                           Name of Listing Handler ro use
          ``result``                          Store the resulting list in context under given
                                              name.
          ==================================  ================================================
  
      Examples::
  
          {% listing 10 of articles.article for "home_page" as obj_list %}
          {% listing 10 of articles.article for category as obj_list %}
          {% listing 10 of articles.article for category with children as obj_list %}
          {% listing 10 of articles.article for category with descendents as obj_list %}
          {% listing 10 from 10 of articles.article as obj_list %}
          {% listing 10 of articles.article, photos.photo as obj_list %}