Add menuconfig example/proof of concept

Still needs documentation and some cleanup.

Interface deliberately kept super simple/clunky to focus on the
concepts. Not something you'd actually want to use.

Sample session:

  $ python Kconfiglib/examples/menuconfig.py Kconfiglib/examples/Kmenuconfig

  ======== Example Kconfig configuration ========

  [*] Enable loadable module support (MODULES)
      Bool and tristate symbols
          [*] Bool symbol (BOOL)
                  [ ] Dependent bool symbol (BOOL_DEP)
                  < > Dependent tristate symbol (TRI_DEP)
                  [ ] First prompt (TWO_MENU_NODES)
          < > Tristate symbol (TRI)
          [ ] Second prompt (TWO_MENU_NODES)
              *** These are selected by TRI_DEP ***
          < > Tristate selected by TRI_DEP (SELECTED_BY_TRI_DEP)
          < > Tristate implied by TRI_DEP (IMPLIED_BY_TRI_DEP)
      String, int, and hex symbols
          (foo) String symbol (STRING)
          (747) Int symbol (INT)
          (0xABC) Hex symbol (HEX)
      Various choices
          -*- Bool choice (BOOL_CHOICE)
                  --> Bool choice sym 1 (BOOL_CHOICE_SYM_1)
                      Bool choice sym 2 (BOOL_CHOICE_SYM_2)
          {M} Tristate choice (TRI_CHOICE)
                  < > Tristate choice sym 1 (TRI_CHOICE_SYM_1)
                  < > Tristate choice sym 2 (TRI_CHOICE_SYM_2)
          [ ] Optional bool choice (OPT_BOOL_CHOICE)

  Enter a symbol/choice name, "load_config", or "write_config" (or press CTRL+D to exit): BOOL
  Value for BOOL (available: n, y): n

  ======== Example Kconfig configuration ========

  [*] Enable loadable module support (MODULES)
      Bool and tristate symbols
          [ ] Bool symbol (BOOL)
          < > Tristate symbol (TRI)
          [ ] Second prompt (TWO_MENU_NODES)
              *** These are selected by TRI_DEP ***
          < > Tristate selected by TRI_DEP (SELECTED_BY_TRI_DEP)
          < > Tristate implied by TRI_DEP (IMPLIED_BY_TRI_DEP)
      String, int, and hex symbols
          (foo) String symbol (STRING)
          (747) Int symbol (INT)
          (0xABC) Hex symbol (HEX)
      Various choices
          -*- Bool choice (BOOL_CHOICE)
                  --> Bool choice sym 1 (BOOL_CHOICE_SYM_1)
                      Bool choice sym 2 (BOOL_CHOICE_SYM_2)
          {M} Tristate choice (TRI_CHOICE)
                  < > Tristate choice sym 1 (TRI_CHOICE_SYM_1)
                  < > Tristate choice sym 2 (TRI_CHOICE_SYM_2)
          [ ] Optional bool choice (OPT_BOOL_CHOICE)

  Enter a symbol/choice name, "load_config", or "write_config" (or press CTRL+D to exit): MODULES
  Value for MODULES (available: n, y): n

  ======== Example Kconfig configuration ========

  [ ] Enable loadable module support (MODULES)
      Bool and tristate symbols
          [ ] Bool symbol (BOOL)
          [ ] Tristate symbol (TRI)
          [ ] Second prompt (TWO_MENU_NODES)
              *** These are selected by TRI_DEP ***
          [ ] Tristate selected by TRI_DEP (SELECTED_BY_TRI_DEP)
          [ ] Tristate implied by TRI_DEP (IMPLIED_BY_TRI_DEP)
      String, int, and hex symbols
          (foo) String symbol (STRING)
          (747) Int symbol (INT)
          (0xABC) Hex symbol (HEX)
      Various choices
          -*- Bool choice (BOOL_CHOICE)
                  --> Bool choice sym 1 (BOOL_CHOICE_SYM_1)
                      Bool choice sym 2 (BOOL_CHOICE_SYM_2)
          -*- Tristate choice (TRI_CHOICE)
                  --> Tristate choice sym 1 (TRI_CHOICE_SYM_1)
                      Tristate choice sym 2 (TRI_CHOICE_SYM_2)
          [ ] Optional bool choice (OPT_BOOL_CHOICE)

  Enter a symbol/choice name, "load_config", or "write_config" (or press CTRL+D to exit): ^D

Unsetting modules demonstrates one reason why it makes sense to have
.type be magic and change from TRISTATE to BOOL without modules
(<> = tristate, [] = bool). The C implementation uses the same trick.
(The original type is still available in .orig_type though.)

Piggyback printing of tristates as n, m, y in the warning for invalid
values in set_value().

1 files changed, 102 insertions, 0 deletions

diff --git a/examples/Kmenuconfig b/examples/Kmenuconfig
new file mode 100644
index 0000000..f1cb67b
--- /dev/null
+++ b/examples/Kmenuconfig
@@ -0,0 +1,102 @@
+mainmenu "Example Kconfig configuration"
+
+config MODULES
+	bool "Enable loadable module support"
+	option modules
+	default y
+
+menu "Bool and tristate symbols"
+
+config BOOL
+	bool "Bool symbol"
+	default y
+
+config BOOL_DEP
+	bool "Dependent bool symbol"
+	depends on BOOL
+
+# Mix it up a bit with an 'if' instead of a 'depends on'
+if BOOL
+
+config TRI_DEP
+	tristate "Dependent tristate symbol"
+	select SELECTED_BY_TRI_DEP
+	imply IMPLIED_BY_TRI_DEP
+
+endif
+
+config TWO_MENU_NODES
+	bool "First prompt"
+	depends on BOOL
+
+config TRI
+	tristate "Tristate symbol"
+
+config TWO_MENU_NODES
+	bool "Second prompt"
+
+comment "These are selected by TRI_DEP"
+
+config SELECTED_BY_TRI_DEP
+	tristate "Tristate selected by TRI_DEP"
+
+config IMPLIED_BY_TRI_DEP
+	tristate "Tristate implied by TRI_DEP"
+
+endmenu
+
+
+menu "String, int, and hex symbols"
+
+config STRING
+	string "String symbol"
+	default "foo"
+
+config INT
+	int "Int symbol"
+	default 747
+
+config HEX
+	hex "Hex symbol"
+	default 0xABC
+
+endmenu
+
+
+menu "Various choices"
+
+choice BOOL_CHOICE
+	bool "Bool choice"
+
+config BOOL_CHOICE_SYM_1
+	bool "Bool choice sym 1"
+
+config BOOL_CHOICE_SYM_2
+	bool "Bool choice sym 2"
+
+endchoice
+
+choice TRI_CHOICE
+	tristate "Tristate choice"
+
+config TRI_CHOICE_SYM_1
+	tristate "Tristate choice sym 1"
+
+config TRI_CHOICE_SYM_2
+	tristate "Tristate choice sym 2"
+
+endchoice
+
+choice OPT_BOOL_CHOICE
+	bool "Optional bool choice"
+	optional
+
+config OPT_BOOL_CHOICE_SYM_1
+	bool "Optional bool choice sym 1"
+
+config OPT_BOOL_CHOICE_SYM_2
+	bool "Optional bool choice sym 2"
+
+endchoice
+
+endmenu