gistfile1.py

class EndTagSet(object):

    def __init__(self, *tags):
        self.tags = set(tags)

    def __contains__(self, token_contents):
        # Grab out the command so we can match on the tag name, not the
        # whole tag contents.
        try:
            command = token_contents.split()[0]
        except IndexError:
            # The template parser will discover this is an empty tag
            # momentarily, so ignore this and let it error.
            return False
        return command in self.tags


@register.tag
def case(parser, token):
    try:
        tag_name, arg = token.contents.split(None, 1)
    except ValueError:
        raise TemplateSyntaxError("%r tag requires an expression argument"
            % token.contents.split(None, 1)[0])

    log.debug("Yay case %r tag! Let's eat some nodes", arg)
    testexpr = parser.compile_filter(arg)
    nodelist = parser.parse(EndTagSet('case', 'default', 'endswitch'))

    if log.isEnabledFor(logging.DEBUG):
        next_token = parser.next_token()
        log.debug("    Ate up through %r", next_token.contents)
        parser.prepend_token(next_token)

    return CaseNode(arg, testexpr, nodelist)