git working tree status

Hi all,

I'd like a way of getting a simple summary of the status of a working tree, for consumption by other programs rather than humans.

Specifically, I'd like to know whether the working tree is:

a) fully 'clean' -- i.e., all changes checked in, no stashes; b) all changes checked in, but there are some stashes; or c) 'dirty' in some way -- new files, uncommitted changes, etc.

The logical way to do this seems to be via an exit code, but the exit code of git status is not currently rich enough. As a result, I'm considering the addition of an option to git status -- perhaps '--is-clean' -- that would provide the required information.

My questions are:

1) Is there already some way of doing this that I've overlooked?
2) Would the preferred approach be an option (git status --is-clean)
or a sub-command (git is-clean)?  A sub-command would probably result
in cleaner internal code, but would also clutter the interface.
3) Is a patch for such a feature likely to be accepted?

Thanks,