Re: [RFC/largely untested/PATCH] sha1_name: interpret ~n as HEAD~n

[Michael J Gruber <git@drmicha.warpmail.net>]

Andreas Schwab venit, vidit, dixit 30.04.2011 11:09:
> Junio C Hamano <gitster@pobox.com> writes:
> 
>> Andreas Schwab <schwab@linux-m68k.org> writes:
>>
>>> Jeff King <peff@peff.net> writes:
>>>
>>>> It also conflicts a little with the shell's "~user" syntax, though
>>>> presumably you don't have users named "1" and "2".
>>>
>>> Well, you sorta do if you did use pushd.
>>
>> Yeah, I was also worried about that.  Or some arcane system
>> misinterpreting "~0" as the home directory of root ;-)
> 
> On non-arcane systems ~0 is expanded to the current directory.
> 
> Andreas.
> 
[cumulative reply :)]

While we could use a short-hand for HEAD also I don't think ~0 really is
a concern.

Regarding consistency:
We try to have reasonable defaults and try to dwim (which are different
things) even if that breaks consistency/systematics, because
useful/reasonable and "what I mean" depend on the context.

"^" resp. ".." and "..." are ambiguous and cannot be resolved easily
because for most commands they can mean two things resp. require two
arguments. (".." and "..." could maybe default do "@{u}..HEAD" etc.)

"~<n>" can only take a revision argument to its left, and also it needs
an argument to its left (as opposed to "^"). Therefore we can default it
unambiguously and without braking any current usage (that I know of).

Regarding rebase -i -<n>:
git-rebase (-i) does not have a log/rev-list like interface at all (just
like git-cherry does not), and introducing an argument which looks like
it did would just increase the user confusion, I'm afraid.

Michael