let label_input input =
match input with
| User_load_in_new_win_event(url) -> L
| User_load_in_win_event(user_window, url) -> L
| User_link_to_new_win_event(user_window, url) -> level_of_url url
| User_link_to_named_win_event(user_window, name, url) -> level_of_url url
| User_close_win_event(user_window) -> L
| User_input_text_event(user_textbox, text, _) -> begin
match user_textbox with
| User_textbox(user_window, nat) ->
match user_window with
| User_window(url, nat2) -> level_of_url url
end
| User_click_button_event(user_button) -> H
| Network_response_event(net_conn, resp) ->
M(domain_of_net_connection net_conn)