Dotted revno "algebra"

[Talden]

> I for one would care *hugely*.  I find there to be a great deal
> of difference in usability between revnos and revids:
>  - Revnos mean something to me.  Sure they're local to a
>    particular branch, but within that frame of reference they
>    provide a partial ordering that I find quite comprehensible,
>    and very useful despite being only partial.
>
>  - I can, and often do, type revnos -- even long ones like your
>    example.  Revids?  Forget it!  (I touch type, so the physical
>    *and mental* context switch of taking my hands off the
>    keyboard to cut'n'paste costs me more than typing a dozen
>    characters.  Of course, waiting for revno generation might
>    cost still more in elapsed time, but even if it does, it
>    *feels* to me like less of a distraction than the context
>    switch does.)

These are both important for me too.

The ordinal nature of the dotted revisions makes them a small enough
chunk of mental material to do a scroll and type without resorting to
copy-paste (I don't like to leave the keyboard unnecessarily either).
Other numeric solutions would likely fit for this purpose too - not
rev-ids though.

The 'comprehensible' aspect for me is the commit number along that
branch (the X in A.B.X) - large numbers at the merge point for
long-lived (usually more complex) work and small numbers for
short-lived branches.  Branch point it useful too, but getting that if
I want to look further is fast enough not to matter as much to me.

If either of these had to go away then I think a replacement would be
less useful to me and I'd be leaning towards tossing them away
entirely and just show some hash (or a shortest unique prefix of one).

--
Talden