[issue10984] argparse add_mutually_exclusive_group should accept existing arguments to register conflicts
paul j3
report at bugs.python.org
Sat Mar 1 00:04:45 CET 2014
paul j3 added the comment:
In http://bugs.python.org/issue11588 (Add "necessarily inclusive" groups to argparse) I propose a generalization to these testing groups that would solve your 'conflicter' case as follows:
usage = 'prog [ --conflicter | [ --opt1 ] [ --opt2 ] ]'
parser = argparse.ArgumentParser(usage=usage)
conflicter = parser.add_argument("--conflicter", action='store_true')
opt1 = parser.add_argument("--opt1", action='store_true')
opt2 = parser.add_argument("--opt2", action='store_true')
@parser.crosstest
def test(parser, seen_actions, *args):
if conflicter in seen_actions:
if 0<len(seen_actions.intersection([opt1, opt2])):
parser.error('--conflicter cannot be used with --opt1 or --opt2')
Groups, as currently defined, cannot handle nesting, and as a consequence cannot handle complex logic. My proposal is to replace groups with user defined conflict tests that would be run near the end of 'parse_args'.
This example shows, I think, that the proposal is powerful enough. I'm not sure about ease of use and logical transparency.
Formatting the usage line is a different issue, though the MultiGroupHelpFormatter that I propose here is a step in the right direction. For now a user written 'usage' is the simplest solution.
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<http://bugs.python.org/issue10984>
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