Created
September 21, 2021 15:59
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argparse.Action like "store", but with an optional modifier
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| import argparse | |
| import sys | |
| from enum import Enum | |
| class Viewport(Enum): | |
| All = "all" | |
| WorkingDirectory = "here" | |
| OwnedByMe = "mine" | |
| # NOTE The property decorator doesn't work on default and choices, | |
| # below; probably due to some Enum metaprogramming magic. As such, | |
| # we have to make do with methods. | |
| @classmethod | |
| def default(cls): | |
| default, *_ = cls | |
| return default | |
| @classmethod | |
| def choices(cls): | |
| return [*cls] | |
| class StoreOptionalModifier(argparse.Action): | |
| def __call__(self, _parser:argparse.ArgumentParser, namespace:argparse.Namespace, values:Viewport, _option_string:str): | |
| setattr(namespace, self.dest, values or Viewport.default()) | |
| p = argparse.ArgumentParser() | |
| p.add_argument("--view", dest="view", metavar="WHAT", | |
| nargs="?", | |
| action=StoreOptionalModifier, | |
| type=Viewport, | |
| choices=Viewport.choices(), | |
| default=argparse.SUPPRESS, | |
| help="show the recoverable files from WHAT") | |
| if __name__ == "__main__": | |
| print(p.parse_args(sys.argv[1:])) |
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