Consistently use 0/1/2 for tristate values

Easier to work with, allowing e.g. direct comparisons with < and >. Make
set_value() take 0, 1, 2 for bool and tristate symbols, and fix other
APIs to match.

Also:

  - Add introductions to various concepts in the module docstring.
    Document some more attributes. Still TODOs.

  - Rename the Config class to Kconfig.

  - Escape " and \ in the name of constant symbols when printing them.
    Also make the (un)escaping 100% consistent with how the C tools do
    it (\ before non-magic character should be unescaped too).

  - Clean up the escaping/unescaping code and provide two public
    escape()/unescape() functions.

  - Export the original MODULES-independent type in orig_type. It's
    needed for printing symbols in the reparsable __str__() Kconfig
    format with just public APIs.

  - Lots of other minor reorganizing and nits all over.

1 files changed, 32 insertions, 31 deletions

diff --git a/examples/print_sym_info.py b/examples/print_sym_info.py
index 2c1b0f0..cc9f50a 100644
--- a/examples/print_sym_info.py
+++ b/examples/print_sym_info.py
@@ -5,48 +5,49 @@
 #   $ make [ARCH=<arch>] scriptconfig SCRIPT=Kconfiglib/examples/print_sym_info.py SCRIPT_ARG=<name>
 #
 # Example output for SCRIPT_ARG=modules:
-# 
-#   config MODULES
-#   	bool
-#   	prompt "Enable loadable module support"
-#   	option modules
-#   	help
-#   	  Kernel modules are small pieces of compiled code which can
-#   	  be inserted in the running kernel, rather than being
-#   	  permanently built into the kernel.  You use the "modprobe"
-#   	  tool to add (and sometimes remove) them.  If you say Y here,
-#   	  many parts of the kernel can be built as modules (by
-#   	  answering M instead of Y where indicated): this is most
-#   	  useful for infrequently used options which are not required
-#   	  for booting.  For more information, see the man pages for
-#   	  modprobe, lsmod, modinfo, insmod and rmmod.
-#   	  
-#   	  If you say Y here, you will need to run "make
-#   	  modules_install" to put the modules under /lib/modules/
-#   	  where modprobe can find them (you may need to be root to do
-#   	  this).
-#   	  
-#   	  If unsure, say Y.
 #
-#   value = n
-#   visibility = y
-#   currently assignable values: n, y
-#   defined at init/Kconfig:1678
+# menuconfig MODULES
+# 	bool
+# 	prompt "Enable loadable module support"
+# 	option modules
+# 	help
+# 	  Kernel modules are small pieces of compiled code which can
+# 	  be inserted in the running kernel, rather than being
+# 	  permanently built into the kernel.  You use the "modprobe"
+# 	  tool to add (and sometimes remove) them.  If you say Y here,
+# 	  many parts of the kernel can be built as modules (by
+# 	  answering M instead of Y where indicated): this is most
+# 	  useful for infrequently used options which are not required
+# 	  for booting.  For more information, see the man pages for
+# 	  modprobe, lsmod, modinfo, insmod and rmmod.
+# 	  
+# 	  If you say Y here, you will need to run "make
+# 	  modules_install" to put the modules under /lib/modules/
+# 	  where modprobe can find them (you may need to be root to do
+# 	  this).
+# 	  
+# 	  If unsure, say Y.
+# 
+# value = n
+# visibility = y
+# currently assignable values: n, y
+# defined at init/Kconfig:1674
 
-import kconfiglib
+from kconfiglib import Kconfig, TRI_TO_STR
 import sys
 
 if len(sys.argv) < 3:
     print('Pass symbol name (without "CONFIG_" prefix) with SCRIPT_ARG=<name>')
     sys.exit(1)
 
-conf = kconfiglib.Config(sys.argv[1])
+conf = Kconfig(sys.argv[1])
 sym = conf.syms[sys.argv[2]]
 
 print(sym)
-print("value = " + sym.value)
-print("visibility = " + sym.visibility)
-print("currently assignable values: " + ", ".join(sym.assignable))
+print("value = " + sym.str_value)
+print("visibility = " + TRI_TO_STR[sym.visibility])
+print("currently assignable values: " +
+      ", ".join([TRI_TO_STR[v] for v in sym.assignable]))
 
 for node in sym.nodes:
     print("defined at {}:{}".format(node.filename, node.linenr))