Re: Useful utility function: org-sort-multi

From: "Ryan C. Thompson" <rct@thompsonclan.org>
Cc: org-mode Mailinglist <emacs-orgmode@gnu.org>
Subject: Re: Useful utility function: org-sort-multi
Date: Sun, 30 Aug 2009 13:55:45 -0700	[thread overview]
Message-ID: <4A9AE751.2080208@thompsonclan.org> (raw)
In-Reply-To: <87ab1hsnte.fsf@gmail.com>

Benjamin Andresen wrote:

> if you have the following list
> * Test Sorting
> ** TODO Charlie
> ** WAITING Beta
> ** TODO Alpha
> ** STARTED Beta
> ** STARTED Charlie
> ** TODO Beta
> ** STARTED Alpha
> ** WAITING Charlie
> ** WAITING Alpha

> calling org-multi-sort with ?o ?a will sort it like this
> * Test Sorting
> ** TODO Alpha
> ** TODO Beta
> ** TODO Charlie
> ** STARTED Alpha
> ** STARTED Beta
> ** STARTED Charlie
> ** WAITING Alpha
> ** WAITING Beta
> ** WAITING Charlie

> but just ?a would completely ignore the TODO, STARTED, WAITING order.

> Thanks Ryan, pretty useful.

> br,
> benny

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That's right, the function relies on the fact that org's sorting is 
stable. So the results of earlier sorts are preserved as much as 
possible in later sorts. Of course, this is really inefficient, but oh well.

As another test case, try using (org-sort-multi ?o ?p) on this:
* Multi-sort test
** DONE [#B]
** TODO [#C]
** STARTED [#C]
** STARTED [#A]
** DONE [#C]
** TODO [#B]
** TODO [#A]
** STARTED [#B]
** DONE [#A]

Anyway, Carsten, if you think this would be useful, feel free to include 
some variant of this in org-mode itself. You'd probably want to 
implement it as a one-pass sort in which the set of sorting criteria 
function as a series of fallbacks for tiebreakers, rather than a series 
of sorts.

Ryan