I was not aware of any implied hierarchy with tags. The order is not
important as far as I know, and what you describe as mix-and-match seems
ok. There is an idea of inheritance, e.g. sub-headings can inherit tags
from higher headings.

In any case, you should be able to use agenda queries to find headings that
are lisp and not emacs, lisp+orgmode, etc.

I am not sure about the org-mode tag. In the past, emacs splits that into
:org:mode: for me.

What do you want to do with the tags?

John

-----------------------------------
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu


On Thu, Feb 1, 2018 at 7:07 AM, Lawrence Bottorff <borgauf@gmail.com> wrote:

> Is it possible to have two or more tags that are "peers," i.e., all equal,
> not in a hierarchy, be in an ad-hoc, as-needed way be hierarchical? For
> example, I have the tags *org-mode, lisp, *and *emacs, *and I want to
> have a header with the tags
>
> * my header    :emacs:org-mode:lisp:
>
> So the above should be an ad-hoc hierarchy of
>
> - emacs
>    - org-mode
>       - lisp
>
> As I understand, the order indicates the level in a hierarchy. True? So
> the above has *emacs* at the top of the tag hierarchy, then *org-mode, *then
> *lisp. *Correct? So yes, I could simply set up this hierarchy. But what I
> really want is to not have these tags in any set hierarchy, rather, be able
> to use them independently, mix-and-match, e.g.,
>
> * Another Header    :emacs:lisp:
>
> or maybe
>
> * Yet Another Header   :lisp:
>
> and this would be just about non-Emacs, non-org-mode Lisp. Is this
> mix-and-match possible?
>
> LB
>