[OE-core] [wic patch 5/5] wic: Use enum like dicts for string constants

[Ed Bartosh]

On Fri, Apr 21, 2017 at 02:11:45PM +0200, Andreas J. Reichel wrote:
> To increase code maintainability, use dictionaries
> as enum-like container for parameter string comparisons.
> 
> Signed-off-by: Andreas Reichel <andreas.reichel.ext at siemens.com>
> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> Signed-off-by: Daniel Wagner <daniel.wagner at siemens.com>
> 
> ---
>  scripts/lib/wic/engine.py | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/scripts/lib/wic/engine.py b/scripts/lib/wic/engine.py
> index 647358287f..1428a73ba8 100644
> --- a/scripts/lib/wic/engine.py
> +++ b/scripts/lib/wic/engine.py
> @@ -35,6 +35,16 @@ from wic import WicError
>  from wic.pluginbase import PluginMgr
>  from wic.utils.misc import get_bitbake_var
>  
> +class StrEnum(dict):
> +    __getattr__ = dict.get
> +
> +ListType = StrEnum({
> +    'LIST_IMAGES': "images",
> +    'LIST_SRC_PLUGINS': "source-plugins" })
> +
> +HelpArg = StrEnum({
> +    'HELP': "help" })
> +
>  logger = logging.getLogger('wic')
>  
>  def verify_build_env():
> @@ -204,14 +214,14 @@ def wic_list(args, scripts_path):
>      if args.list_type is None:
>          return False
>  
> -    if args.list_type == "images":
> +    if args.list_type == ListType.LIST_IMAGES:
>  
>          list_canned_images(scripts_path)
>          return True
> -    elif args.list_type == "source-plugins":
> +    elif args.list_type == ListType.LIST_SRC_PLUGINS:
>          list_source_plugins()
>          return True
> -    elif len(args.help_for) == 1 and args.help_for[0] == 'help':
> +    elif len(args.help_for) == 1 and args.help_for[0] == HelpArg.HELP:
>          wks_file = args.list_type
>          fullpath = find_canned_image(scripts_path, wks_file)
>          if not fullpath:

I'm not sure if this increases maintainability, but it definitely increases code complexity and
decreases readability. Can you explain the idea in a bit more detailed way?

--
Regards,
Ed