paul j3 added the comment: This patch adds this `nargs='{m,n}'` or `nargs=(m,n)` feature.
It builds on the `better nargs error message` patch in http://bugs.python.org/msg187754 It includes an argparse.rst paragraph, changes to argparse.py, and additions to test_argparse.py. The tests include those proposed by wm, rewritten to use the ParserTestCase framework where possible. I did not give a lot of thought to test names. The coverage could also use further thought. As WM noted some range cases are the equivalent to existing nargs options ('{1,}'=='+'). I did not attempt to code or test such equivalences. Since the '{0,}' form uses regex matching just like '*', I don't think there is any advantage to making such a translation. I convert the tuple version (m,n) to the re string '{m,n}' during the add_argument() testing. So it is the string form that is added to the parser action. This is also the format that appears in usage. The documentation paragraph is: '{m,n}'. m to n command-line arguments are gathered into a list. This is modeled on the Regular Expression use. '{,n}' gathers up to n arguments. '{m,}' gathers m or more. Thus '{1,}' is the equivalent to '+', and '{,1}' to '?'. A tuple notation is also accepted, '(m,n)', '(None,n)', '(m,None)'. For example: >>> parser = argparse.ArgumentParser(prog='PROG') >>> parser.add_argument('--foo', nargs='{2,4}') >>> parser.parse_args('--foo a b c'.split()) Namespace(foo=['a', 'b', 'c']) >>> parser.parse_args('--foo a'.split()) usage: PROG [-h] [--foo FOO{2,4}] PROG: error: argument --foo: expected {2,4} arguments ---------- Added file: http://bugs.python.org/file30187/nargsrange.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue11354> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com