From a python-dev email from Neal Becker, copied here so it won't get lost.
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steven.bethard@gmail.com made a very nice module for me to enhance argparse called argparse_bool.py, which contains ConfigureAction.  This will allow a boolean value to be set very like the gnu configure style:

--foo
--with-foo
--without-foo
--no-foo
--foo=yes
--foo=no

I've been happily using it, and I think it would be of sufficient general interest to include it with the standard library.

Are we sure we want three or four ways to spell the same thing? --foo and --no-foo seem a useful couple to me, and --with-foo/--without-foo cater to different use cases. Perhaps it would be ok to have a SwitchAction (or FlagAction) for --thing/--no-hing and one ConfigureAction for the --with[out]-* style.

I'm looking into making a patch from this for py3k, and have the following observations:

1. I agree with merwok, at the moment the monolithic ConfigureAction is a bit excessive for most uses (other than maybe emulating ./Configure...). I vote we split it to FlagAction and ConfigureAction.
2. I don't think this should be added as an argparse builtin/registered action (like action='store' or action='count'), but rather as a ready-made user-action in a separate namespace (from argparse.actions import FlagAction)

Given feedback that these two decisions seem sane, I'd be happy to produce a patch against recent py3k.

I think you can go ahead and produce a patch. Don’t start splitting argparse into a package now though, this is a sensible decision IMO but has to be agreed by the maintainer; just add FlagAction and ConfigureAction to argparse for now.

Some useful tips to make patches: http://www.python.org/dev/patches/

I think this should be updated so that nargs=0 is allowed, so that you can only do --foo/--no-foo and don't clutter up the help/interface with --foo [FOO] --no-foo=[FOO]

You can do this by adding nargs to the ConfigureAction.__init__ and passing that through to super, and then updating __call__ to check 'if value is None or value == []:' instead of the None.

I think FlagAction should implement strictly boolean options, that is --foo and --no-foo, without arguments at all.

For ConfigureAction, there is a precedent (unless I’m mistaken) in configure, which permits such things:
  --without-unicode
  --with-unicode=ucs4
  --with-unicode (uses default value for arg)

I say we focus on the simple FlagAction for this bug and keep ConfigureAction for another patch.

Yaniv: Can you give us a status update?

On the off chance that someone was waiting for feedback from me, I'll say:

(1) A simple boolean --foo/--no-foo action seems useful to me. I would probably call it BooleanOptionalAction rather than FlagAction. (Almost anything could be considered a "flag".)

(2) At the moment, argparse doesn't supply any actions, so I don't think we should make a separate namespace for them. If it starts to grow a list of such actions, we can add a separate namespace later. (And given that the name will end with "Action", I think it should be pretty clear without the namespace.)