Hello,

Reasonably frequently I find myself needing to pass a date as a command line argument to a Python script I've written. Currently, argparse does not have a built support for dates - this adds a new class to argparse (much like the existing FileType) that parses arguments to datetime.date instances.

Example:

      >>> parser = argparse.ArgumentParser()
      >>> parser.add_argument('--start', type=argparse.DateType('%d/%m/%Y))
      >>> parser.add_argument('end', type=argparse.DateType())
      >>> parser.parse_args(['--start', '01/02/2015', '2015-01-03'])
      Namespace(end=datetime.date(2015, 1, 3), start=datetime.date(2015, 1, 2))


I think this would be a useful addition to the standard library, a quick Google shows that many people roll their own version of this anyway.

Support for datetime.datetime and perhaps even datetime.timedeltas might be good too, but date/times get a bit more complicated (timezones in general and varying support for the '%z' format string which is required to default to an ISO8601 date time).

Cheers,

Pete