kconfig: Refactor kconfig.py to use __main__ and argparse

Kconfig.py is not following the de-facto (real?) coding standards of
Zephyr. This commit refactors kconfig.py with two changes:

Use __main__ and def main().

Use argparse instead of sys.argv.

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>

scripts/kconfig/kconfig.py

@@ -2,34 +2,33 @@
 # Modified from: https://github.com/ulfalizer/Kconfiglib/blob/master/examples/merge_config.py
 from kconfiglib import Kconfig, Symbol, BOOL, STRING, TRISTATE, TRI_TO_STR
 import sys
+import argparse
 
-if len(sys.argv) < 5:
-    print('usage: {} Kconfig dotconfig autoconf conf1 [conf2 ...]'
-          .format(sys.argv[0]))
-    sys.exit(1)
+def main():
+    parse_args()
 
-print("Parsing Kconfig tree in {}".format(sys.argv[1]))
-kconf = Kconfig(sys.argv[1])
+    print("Parsing Kconfig tree in {}".format(args.kconfig_root))
+    kconf = Kconfig(args.kconfig_root)
 
-# Enable warnings for assignments to undefined symbols
-kconf.enable_undef_warnings()
+    # Enable warnings for assignments to undefined symbols
+    kconf.enable_undef_warnings()
 
-# This script uses alldefconfig as the base. Other starting states could be set
-# up here as well. The approach in examples/allnoconfig_simpler.py could
-# provide an allnoconfig starting state for example.
+    # This script uses alldefconfig as the base. Other starting states could be set
+    # up here as well. The approach in examples/allnoconfig_simpler.py could
+    # provide an allnoconfig starting state for example.
 
-print("Using {} as base".format(sys.argv[4]))
-for config in sys.argv[5:]:
+    print("Using {} as base".format(args.conf_fragments[0]))
+    for config in args.conf_fragments[1:]:
         print("Merging {}".format(config))
-# Create a merged configuration by loading the fragments with replace=False
-for config in sys.argv[4:]:
+    # Create a merged configuration by loading the fragments with replace=False
+    for config in args.conf_fragments:
         kconf.load_config(config, replace=False)
 
 
-# Print warnings for symbols whose actual value doesn't match the assigned
-# value
+    # Print warnings for symbols whose actual value doesn't match the assigned
+    # value
 
-def name_and_loc(sym):
+    def name_and_loc(sym):
         # Helper for printing symbol names and Kconfig file location(s) in warnings
 
         if not sym.nodes:
@@ -40,7 +39,7 @@ def name_and_loc(sym):
             ", ".join("{}:{}".format(node.filename, node.linenr)
                       for node in sym.nodes))
 
-for sym in kconf.defined_syms:
+    for sym in kconf.defined_syms:
         # Was the symbol assigned to?
         if sym.user_value is not None:
             # Tristate values are represented as 0, 1, 2. Having them as
@@ -57,16 +56,36 @@ for sym in kconf.defined_syms:
                       file=sys.stderr)
 
 
-# Turn the warning for malformed .config lines into an error
-for warning in kconf.warnings:
+    # Turn the warning for malformed .config lines into an error
+    for warning in kconf.warnings:
         if "ignoring malformed line" in warning:
             print("Aborting due to malformed configuration settings",
                   file=sys.stderr)
             sys.exit(1)
 
 
-# Write the merged configuration
-kconf.write_config(sys.argv[2])
+    # Write the merged configuration
+    kconf.write_config(args.dotconfig)
 
-# Write the C header
-kconf.write_autoconf(sys.argv[3])
+    # Write the C header
+    kconf.write_autoconf(args.autoconf)
+
+
+def parse_args():
+    global args
+
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter
+    )
+
+    parser.add_argument("kconfig_root")
+    parser.add_argument("dotconfig")
+    parser.add_argument("autoconf")
+    parser.add_argument("conf_fragments", metavar='conf', type=str, nargs='+')
+
+    args = parser.parse_args()
+
+
+if __name__ == "__main__":
+    main()