Re: argparse -- mutually exclusive sets of arguments?
On Fri, Nov 23, 2012 at 11:46 AM, Roy Smith wrote:
> My command either takes two positional arguments (in which case, both
> are required):
>
> $ command foo bar
>
> or the name of a config file (in which case, the positional arguments
> are forbidden):
>
> $ command --config file
>
> How can I represent this with argparse; add_mutually_exclusive_group()
> isn't quite the right thing. It could specify that foo and --config are
> mutually exclusive, but not (as far as I can see) the more complicated
> logic described above.
I don't think you could even do the former. An argument must be
optional in order to be mutually exclusive with anything. This works,
however:
parser = argparse.ArgumentParser()
group = parser.add_mutually_exclusive_group(required=True)
group.add_argument('--config', type=file)
group.add_argument('--foobar', nargs=2, metavar=('FOO', 'BAR'))
print parser.parse_args()
Downsides are that the resulting interface is a little more formal and
a little less friendly, and unless you customize the action you'll
wind up with a 2-element 'foobar' arg instead of separate 'foo' and
'bar' args.
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Re: argparse -- mutually exclusive sets of arguments?
On 23 November 2012 18:46, Roy Smith wrote:
> My command either takes two positional arguments (in which case, both
> are required):
>
> $ command foo bar
>
> or the name of a config file (in which case, the positional arguments
> are forbidden):
>
> $ command --config file
>
> How can I represent this with argparse; add_mutually_exclusive_group()
> isn't quite the right thing. It could specify that foo and --config are
> mutually exclusive, but not (as far as I can see) the more complicated
> logic described above.
Do you need to use argparse?
If not, I've been recommending docopt due to its power and simplicity:
-START -
"""
Command.
Usage:
command
command --config=
Options:
foo The egg that spams
bar The spam that eggs
--config= The config that configures
"""
from docopt import docopt
if __name__ == '__main__':
arguments = docopt(__doc__)
print(arguments)
- END
- USAGE -
%~> python simple_docopt.py foobar barfoo
{'--config': None,
'': 'barfoo',
'': 'foobar'}
%~> python simple_docopt.py foobar
Usage:
simple_docopt.py
simple_docopt.py --config=
%~> python simple_docopt.py --config=turtle.conf
{'--config': 'turtle.conf',
'': None,
'': None}
%~> python simple_docopt.py --config=turtle.conf not allowed
Usage:
simple_docopt.py
simple_docopt.py --config=
--- END USAGE ---
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Re: argparse -- mutually exclusive sets of arguments?
On 11/23/2012 1:46 PM, Roy Smith wrote: My command either takes two positional arguments (in which case, both are required): $ command foo bar or the name of a config file (in which case, the positional arguments are forbidden): $ command --config file How can I represent this with argparse; add_mutually_exclusive_group() isn't quite the right thing. It could specify that foo and --config are mutually exclusive, but not (as far as I can see) the more complicated logic described above. Make the two positional arguments be one duple? Or tell argparse that all three are optional and handle the 'more complicated logic' in your own code after argparse returns. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
argparse -- mutually exclusive sets of arguments?
My command either takes two positional arguments (in which case, both are required): $ command foo bar or the name of a config file (in which case, the positional arguments are forbidden): $ command --config file How can I represent this with argparse; add_mutually_exclusive_group() isn't quite the right thing. It could specify that foo and --config are mutually exclusive, but not (as far as I can see) the more complicated logic described above. -- http://mail.python.org/mailman/listinfo/python-list
