Re: deleting hidden parts of sparse trees

[Dan Davison <davison@stats.ox.ac.uk>]

On Mon, Jul 07, 2008 at 09:48:37AM -0700, Carsten Dominik wrote:
>
> On Jul 7, 2008, at 9:44 AM, Carsten Dominik wrote:
>>
<...>
>>
>> Do I need to mention that this will be a dangerous operation, deleting
>> lots of invisible text?  You might find out only ater it is too late
>> to recover.
>
>
> Even much more dangerous then I thought, the command shown above
> actually deletes anything covered by overlays, not only outline
> overlays.  Just one misplaced parenthesis......
>
> Here is the corrected version.
>
> (defun outline-delete-invisible ()
>   "Delete all text covered by overlays with `invisible' property  
> `outline'."
>   (interactive)
>   (let ((ovls (overlays-in (point-min) (point-max))) o)
>     (while (setq o (pop ovls))
>       (and (eq (overlay-get o 'invisible) 'outline)
> 	   (delete-region (overlay-start o) (overlay-end o))))))
>

Excellent! Thanks for the lesson.

My motivation for the request is as follows. I have a 'master' org
file (a database of plant photos arranged in a taxonomic hierarchy),
and I want to publish it as html, together with html versions of
various sparse trees derived from that master file according to tag
matching criteria etc. One option would be to write my own publishing
function, that creates each sparse tree and calls org-export-visible
on it. But I'd be recoding a load of stuff that has already been
addressed by org-publish. However, with the new function, I can create
the org-files corresponding to the sparse trees, and then let
org-publish-org-to-html deal with the master and the derived org files
in one go, which is a much better solution IMO.

DAn

p.s. warning heeded: I copy to a temp buffer, create sparse tree
and delete invisible in there.