[Orgmode] deleting hidden parts of sparse trees

[Dan Davison]

I'd like to be able to create a 'pruned' tree -- I am thinking of an
operation that is similar to sparse tree creation, but which results
in the deletion (not just folding) of all subtrees that contain no
matching entries.

I don't think this currently exists as such (?), but it is possible to do
what I want by (1) creating a sparse tree, and (2) org-export-visible,
selecting the 'keep-buffer' option. So that's good. However, I don't
know how to do it programmatically, because org-export-visible has
interactive keyboard input. (Or am I just exposing my ignorance
here??)  I've looked at the code, and what occurs to me is to hack out
the middle bit of org-export-visible as a separate function, say
org-prune-invisible or something. I sort of tried. It, err, didn't
work. Anyone think this would be worth doing? (The functionality, if
not via my suggested route)

Dan