Message112353
It is intentional that you have to specify both "/foo" and "+foo" if you want them to be aliases for the same argument. A common use case for prefix_chars is to define "+x" and "-x" options, which usually mean different things.
As far as the current issue, I believe the current behavior is buggy - an argument that you can never use is added to the parser automatically:
>>> parser = argparse.ArgumentParser(prefix_chars='+')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/bethard/Documents/projects/python/2.X/Lib/argparse.py", line 1569, in __init__
help=_('show this help message and exit'))
File "/Users/bethard/Documents/projects/python/2.X/Lib/argparse.py", line 1246, in add_argument
kwargs = self._get_optional_kwargs(*args, **kwargs)
File "/Users/bethard/Documents/projects/python/2.X/Lib/argparse.py", line 1369, in _get_optional_kwargs
raise ValueError(msg % tup)
ValueError: invalid option string '-h': must start with a character '+'
Yes you could explicitly specify add_help=True, but I think using an appropriate prefix character is actually the right behavior. |
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Date |
User |
Action |
Args |
2010-08-01 16:46:24 | bethard | set | recipients:
+ bethard, doughellmann, ted.turocy |
2010-08-01 16:46:24 | bethard | set | messageid: <1280681184.32.0.841256652031.issue9444@psf.upfronthosting.co.za> |
2010-08-01 16:46:22 | bethard | link | issue9444 messages |
2010-08-01 16:46:21 | bethard | create | |
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