Re: [RFC PATCH v2] shortlog: add group-by options for year and month

> If you give up the regex thing, then that naturally falls out as
> (imagining we learn about authordate as a placeholder):
>
>   git shortlog --group='%(authordate:format=%Y-%n) %an'
>
> without having to implement multiple groupings as a specific feature
> (which is both more code, but also has user-facing confusion about when
> --group overrides versus appends). That also skips the question of which
> --group-by-regex applies to which --group-by-value.
>
> I do agree the regex thing is more flexible, but if we can't come up
> with a case more compelling than subsystem matching, I'd just as soon
> add %(subject:subsystem) or similar. :)