%:::%                   ::: hack solution
PAGE_404_ROUTE          Default 404 page
attach_attribs          Attach 'router-hidden' class to single page UI
                        content
callback_mapping        Create a mapping between a UI element and a
                        server callback.
change_page             Change the currently displayed page.
cleanup_hashpath        Formats a URL fragment into a hashpath starting
                        with "#!/"
create_router_callback
                        Internal function creating a router callback
                        function. One need to call router callback with
                        Shiny input and output in server code.
disable_bootstrap_on_bookmark
                        Fix conflicts when some bookmark uses bootstrap
extract_link_name       Extract link name
get_page                Convenience function to retrieve just the
                        "page" part of the input.
get_query_param         Get Query Parameters
get_url_hash            Internal function to get url hash with #!.
is_page                 Is page
log_msg                 Helper function to print out log messages into
                        Shiny using cat() and stderr(), as described on
                        https://shiny.rstudio.com/articles/debugging.html
make_router             Creates router.
page404                 404 page
parse_url_path          Parse url and build GET parameters list
route                   Create single route configuration.
route_link              Route link
router_server           Create router pages server callback
router_ui               Creates router UI
valid_path              Internal function that validates that path is
                        defined in routes.
