[O] Thesaurus terms as org tags -- feature request

[John Tait]

Dear all

Some time ago I floated a "tag hierarchy" idea for org-mode. It didn't
gain much interest (through I received some very kind replies).

http://lists.gnu.org/archive/html/emacs-orgmode/2011-03/msg01393.html

There are other similar ideas here.

http://lists.gnu.org/archive/html/emacs-orgmode/2010-10/msg01171.html

http://lists.gnu.org/archive/html/emacs-orgmode/2010-10/msg00611.html

What I've discovered since then is that what we are trying to reinvent
is a thesaurus concept, including a controlled vocabulary concept.
Thesauri seem to be well understood, and are standardised by ISO 2788.

What I am looking for then is a way of managing org tags using a very
simple thesauri terms -- inside an org file.

There's software out there to manage thesauri, but I think would be
fantastic to instead build taxonomies inside org-mode and use this to
drive org exports.

The problem I'm trying to solve is that, in big publishing projects,
the number of tags can grow and might eventually need to be managed
outside org-mode. (I'm already keeping lists of my tags inside
org-mode tables.)

What I would love to do is build a simple taxonomy of tags from a
controlled vocabulary -- that I can manage entirely inside org-mode.

Then we could:
 a) have an orderly list of tags (using the thesaurus "USE" concept,
etc.) to restrict tag bloat, and in fact have a controlled list of
tags/terms.
 b) allow nesting of tags (using the thesuaris Broader Term (BT) and
Narrower Term (NT) concepts).

This would allow export of, say, :colour: to export :red: :green: and
:blue:. It would also allow publishing project to be managed by
arranging NT/BT in one place in the org file, rather than
micromanaging tags in headings. Additionally, tags could belong to
more than one taxonomy in the same publishing project.

(The dreaded DITA 1.2 spec now has something like this in the guise of
Subject Scheme maps. But I don't want to look at DITA again.)

http://docs.oasis-open.org/dita/v1.2/cs01/spec/common/subjectScheme.html

I hope you know what I am on about...thanks again for your time.

John Tait