Ben Finney <ben+pyt...@benfinney.id.au> writes:
> Miki Tebeka <miki.teb...@gmail.com> writes:
> > The way I'm doing it currently is:
> > ...
> > no_edit = 'no-edit'
> > parser.add_argument('-e', '--edit', help='open editor on log',
> > nargs='?',
> > default=no_edit)
>
> There is a built-in “no value specified” value in Python: the None
> singleton. The ‘argparse’ library uses this for the argument default
> already, so you don't need to fuss with your own special handling
> <URL:http://docs.python.org/library/argparse.html#default>.
Miki Tebeka <miki.teb...@gmail.com> writes:
> The problem with this approach is that in both cases of not specifying
> -e and with -e with no argument the value of args.edit is None.
Okay. Then instead of a string, which has a chance of being used as the
actual value, I recommend you instead, make a guaranteed-unique sentinel
value::
NO_EDITOR = object()
parser.add_argument(
'-e', '--edit', help='open editor on log', nargs='?',
default=NO_EDITOR)
# …
if args.edit is not NO_EDITOR:
# start the editor
--
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`\ fascinated by the mere supernatural …” —Joseph Conrad, _The |
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Ben Finney
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