Re: Itches with the current rev spec

> 4. Every command is free to interpret positive and negative commits as
> it sees fit.  Since there is no ordering, it must never treat one
> negative commit differently from another negative commit, or one
> positive commit differently from another positive commit.
> 
> show takes a list of positive commits and shows all of them.
> 
> log will show all the commits reachable from positive commits, and
> exclude all the commits reachable from negative commits.  Here, the
> "list of commits" are interpreted differently from the show case.
> 
> diff can either take two positive commits or one positive + one
> negative commit.  In the latter case, it swaps the arguments and
> treats both as positive commits.
> 
> rebase can take one negative commit and one positive commit.  The
> commits reachable from the positive commit, but not from the negative
> commit are replayed onto the negative commit.  Now, we can use --onto=
> to override the commit onto which to replay.  But the fundamental
> constraint remains: rebase _cannot_ make this --onto= parameter part
> of the normal rev spec (we only have two types of commits: positive
> and negative to which we can assign different meanings).
> --