CLI Arguments That Call Functions?
Ian Kelly
ian.g.kelly at gmail.com
Thu Jun 18 14:55:34 EDT 2015
On Thu, Jun 18, 2015 at 11:56 AM, Tony the Tiger <tony at tiger.invalid> wrote:
> I would have assumed there would be something built in to the
> ArgumentParser, but I can't detect anything that seems to do what I want,
> so I wrote the following:
[SNIP]
> So, is there something already in the Python libs? Do I continue with
> this? Or what?
>
> There ought to be something already built in to Python, but I think I've
> missed it. Sure hope so. I'd hate to continue with this mess.
You can specify custom actions for arguments. See
https://docs.python.org/3.4/library/argparse.html#action-classes
For example (untested):
class AppendCallable(argparse.Action):
def __call__(self, parser, namespace, values, option_string):
callables = getattr(namespace, self.dest, None) or []
callables.append(functools.partial(self.const, *values))
setattr(namespace, self.dest, callables)
def main():
parser = argparse.ArgumentParser()
parser.add_argument(
'-a', '--alfa',
action=AppendCallable,
const=option_alfa,
dest='callables',
nargs=1,
type=int)
parser.add_argument(
'-b', '--bravo',
action=AppendCallable,
const=option_bravo,
dest='callables',
nargs=0)
args = parser.parse_args()
for callable in args.callables:
callable()
You might also be interested in reading
https://docs.python.org/3.4/library/argparse.html#sub-commands in case
that's related to what you're trying to accomplish.
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