def routablepageurl(context, page, url_name, *args, **kwargs):
    """
    ``routablepageurl`` is similar to ``pageurl``, but works with
    ``RoutablePage``\s. It behaves like a hybrid between the built-in
    ``reverse``, and ``pageurl`` from Wagtail.

    ``page`` is the RoutablePage that URLs will be generated from.

    ``url_name`` is a URL name defined in ``page.subpage_urls``.

    Positional arguments and keyword arguments should be passed as normal
    positional arguments and keyword arguments.
    """
    request = context['request']
    base_url = page.relative_url(request.site)
    routed_url = page.reverse_subpage(url_name, args=args, kwargs=kwargs)
    return base_url + routed_url