flow of dialogs/user-interactions:
  -----------------------------------------------------------------------------------------
  |                                        LEGEND                                         |
  |---------------------------------------------------------------------------------------|
  | entry-point: | FunctionName()              | function name                            |
  | entry-point: | FunctionName()->[STATE_VAR] | function setting state var(s) implicitly |
  | prompt:      | ->[STATE_VAR]*              | prompt setting state var(s)              |
  | prompt:      | ->translation_key           | prompt setting no state var(s)           |
  | prompt:      | ->`external_program`        | prompt launching an interactive program  |
  | antecedent:  | ?_resp                      | switch on user response                  |
  | antecedent:  | ?_[STATE_VAR]*              | switch on state var(s)                   |
  | consequent:  | -->FunctionName             | proceed to next function                 |
  |----------------------------------------------------------------------------------------
  |  NoticeIntro()                      |  Init()->[INSTALL][KEYRING]              |
  |  -->Init                            |  -->SelectLogins                         |
  |--------------------------------------------------------------------------------|
  |  SelectLogins()                     |  NoticeCustomize()                       |
  |  ->ROOT_PASS                        |  -->SelectDefaults                       |
  |  ->dlg_user-*                       |                                          |
  |    ?_yes                            |                                          |
  |      ->USER_LOGIN                   |                                          |
  |      ->USER_PASS-->NoticeCustomize  |                                          |
  |    ?_no----------->NoticeCustomize  |                                          |
  |-------------------------------------|------------------------------------------|
  |  SelectDefaults()                   |  SelectPartition()                       |
  |  ->[INSTALL]&[BASE]&[INIT]          |  ->DEVICE                                |
  |    [WMDE]                           |  ->PART_METHOD                           |
  |    [HOSTNAME]&[TIMEZONE]&[KEYMAP]&  |    ?_auto---->SelectBoot                 |
  |               [LOCALES]&[LANGUAGE]  |    ?_manual-->SelectBoot                 |
  |    ?_yes-->SelectPartition          |                                          |
  |    ?_no--->SelectPartition          |                                          |
  |-------------------------------------|------------------------------------------|
  |  SelectBoot()                       |  SelectBase()                            |
  |  ->BOOT                             |  ?_[INSTALL]&[BASE]&[INIT]-->SelectWmde  |
  |  ?_grub-->NoticeReady               |  ->INSTALL                               |
  |  ?_none-->NoticeReady               |  ->BASE                                  |
  |                                     |  ->INIT--------------------->SelectWmde  |
  |-------------------------------------|------------------------------------------|
  |  SelectWmde()->[WMDE]               |  SelectEnv()                             |
  |  ?_[WMDE]-->SelectEnv               |  ?_[HOSTNAME]&[TIMEZONE]&[KEYMAP]&       |
  |  ->dlg_wmde                         |    [LOCALES]&[LANGUAGE]-->NoticeReady    |
  |    ?_yes                            |  ->HOSTNAME                              |
  |      ->WMDE-->SelectEnv             |  ->TIMEZONE                              |
  |    ?_no------>SelectEnv             |  ->KEYMAP                                |
  |                                     |  ->LOCALES                               |
  |                                     |  ->LANGUAGE-->NoticeReady                |
  |-------------------------------------|------------------------------------------|
  |  NoticeReady()                      |  Partition()                             |
  |  -->Partition                       |    ?_[PART_METHOD:auto]-->InstallPkgs    |
  |                                     |    ?_[PART_METHOD:manual]                |
  |                                     |      ->`partitioner`                     |
  |                                     |      ->ROOT_PART                         |
  |                                     |      ->BOOT_PART                         |
  |                                     |      ->HOME_PART--------->InstallPkgs    |
  |-------------------------------------|------------------------------------------|
  |  InstallPkgs()                      |  ConfigChroot()                          |
  |  -->ConfigChroot                    |  -->NoticeDone                           |
  |-------------------------------------|------------------------------------------|
  |  NoticeDone()                       |  Cleanup()                               |
  |  -->Cleanup                         |  -->exit                                 |
  ----------------------------------------------------------------------------------