Parser ->                                        ScreenMode Parser ->                              UserRole Parser ->
Arg Rq : ^&HTTPRequest                           Arg Rq : HTTPRequest                              Arg Rq : HTTPRequest

Rq.                                              Rq.Domain_name = <                                ...
 User_role = UserRole Rq                                            'www.example.net' 
 Screen_mode = ScreenMode Rq                                        'light.example.net'            /
;                                                                   'mobile.example.net'
                                                                  > >> <
/                                                                   SCREEN_HTML 
                                                                    SCREEN_LIGHT 
                                                                    SCREEN_MOBILE
                                                                  >
                                                 
                                                 >>
                                                 Exit ERR_SCREEN_MODE

                                                 /