Re: Random tag-related thoughts

[Carsten Dominik <dominik@science.uva.nl>]

On Nov 23, 2006, at 0:54, Bastien wrote:

> Hi Carsten and list,
>
> just a few midnight thoughts on tags.
>
> 0) regexp matching
>
>    Let's say we have :tag0: and :tag1: - then we want C-c \ to match
>    all :tag.: - would that be possible?

You could use org-occur for doing something like this:

C-c / :tag.: RET

> 1) numeric tagging
>
>    Imagine we use numeric tags like :000: :001: 002: etc.  Sometimes
>    and somehow we want to match tags between :001: and :X: (X being a
>    number between 0 and 999:) - can we achieve this?
>
>    (Actuallay i stumbled on this while tagging programming tasks with
>    expected version numbers but was stuck because i couldn't look up
>    for tags between two versions.)

I guess the best for this would be to write your own little helper 
function
that produces the tag list and then calls org-sparse-tree.  Something
along the lines of (untested):

(defun my-org-tag-range-tree (arg base n1 n2)
   "Tags sparse tree for a range of numbered tags."
   (interactive "P\nsBase: \nnStart: \nnEnd: ")
   (let ((match "") (n n1) numbers)
     (if (> n1 n2) (setq n n2 n2 n1))
     (while (<= n n2) (push n numbers) (setq n (1+ n)))
     (setq match (mapconcat (lambda (x)
			     (format "%s%03d" base x))
			   numbers "|"))
     (message match)
     (org-tags-sparse-tree arg match)))

> 2) grouping tags
>
>    { tag1 tag2 } is for mutually exclusive tags
>
>    What about [ tag1 tag2 (tag)] for grouping tags - "(tag)" being the
>    tag-name of the group (i.e. matching all tags in this group)?

I have seen this request before (I think from Tim).  But you could also
define custom searches for that list of tags.  Still, this remains an
interesting idea.

- Carsten