New submission from Michael.Elsdörfer <[email protected]>:
>>> parser = argparse.ArgumentParser()
>>> subparsers = parser.add_subparsers(title="commands")
>>> subparser = subparsers.add_parser('make')
>>> parser.add_argument('jobs', nargs='*')
>>> parser.print_help()
usage: [-h] {make} ... [jobs [jobs ...]]
While the printed usage looks innocuous enough, argparser isn't actually able
to parse this the way I expect: The positional argument never get's to handle
any jobs given, as apparently everything after the command is handled by the
subparser:
>>> parser.parse_args(['make', 'something'])
usage: make [-h]
make: error: unrecognized arguments: something
It seems that argparse, upon determining that the subparser can't handle a
positional argument, could break out of the subparser, and let the parent
parser continue. If necessary, as further help for argparse on how to resolve
such situations, a parameter could be added to add_subparsers() which would
allow the user to indicate that this group of subparsers should not support
positional arguments.
The usage string should then print as:
>>> parser.print_help()
usage: [-h] {make} [jobs [jobs ...]]
That is, without the "..." after the command.
Finally, if it is decided that the feature will not be added, argparse should
not allow the user to add positional arguments after a subparser.
----------
components: Library (Lib)
messages: 113229
nosy: elsdoerfer
priority: normal
severity: normal
status: open
title: argparse: combine subparsers with global positional args
type: feature request
versions: Python 2.7, Python 3.1, Python 3.2, Python 3.3
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Python tracker <[email protected]>
<http://bugs.python.org/issue9540>
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