Re: Shared subtrees?

[Samium Gromoff <_deepfire@feelingofgreen.ru>]

On Mon, 6 Dec 2010 10:43:17 -0700, Samuel Wales <samologist@gmail.com> wrote:
> Perhaps you can provide examples?  I am not sure if you are referring
> to virtual nodes (virtual regions do not exist in current Emacs,
> although it would be good; kludges might be possible with e.g.
> overlays but are not ideal), graph theoretic structures (ID markers
> implement this in a general way), including text in export (we've
> discussed it but not come up with a general solution yet), or
> something else.

With ten minutes of googling I couldn't figure out what virtual nodes
correspond to, in the context of Emacs (modulo the somewhat irrelevant
Info's virtual-nodes), besides them sounding like something vaguely useful
in implementing the feature I had in mind.

Virtual regions (a presentation of something of synthetic nature, which
is not directly backed by a buffer's region) sound exactly like the best
building block I'd imagine for the implementation of the said feature.

I did refer to the concept of 'partial order', a graph-theoretic
structure indeed.  I did so to illustrate the difference with the usual
tree, where no branches ever join, so none of them ever share identical
children.

I did not refer to including text in export, I'm more interested in the
editing of the partial order.

-- 
regards,
  Samium Gromoff
--
"Actually I made up the term 'object-oriented', and I can tell you I
did not have C++ in mind." - Alan Kay (OOPSLA 1997 Keynote)