Re: Expose value-begin and value-end instead of just value in org-element API

[Nicolas Goaziou <mail@nicolasgoaziou.fr>]

Hello,

John Kitchin <jkitchin@andrew.cmu.edu> writes:

> Wow. I would not have guessed either one of these! Thanks for sharing
> them. Is that documented somewhere? 

[...]

> For elements with a :contents-begin where does :post-affiliated come in?

See <https://orgmode.org/worg/dev/org-element-api.html>

> Once you get the idea, maybe, but this approach seems specific to
> src-blocks (maybe any block) where there are delimiting lines. It
> doesn't work on all elements (which to be fair was not claimed). I think
> the OP was interested in something more consistent, which I am
> sympathetic to.

Some elements are very different from others. What would be the innards
of an horizontal line or a planning line?

> Some things aren't clear to me what should happen though, especially in
> composite elements like tables and plain lists. E.g. To just select a
> table without the affiliated lines, one can use :contents-begin and
> :contents-end, once you get the table element (e.g. by walking up the
> :parent chain if you are in a cell or row).
>
> In the absence of a single way, maybe there could be a small number of
> ways to do this? How many cases do you think there are?
>
> - blocks (which have :value)
> - composite elements (which have :contents-begin/end and/or non-nil :parents)
> - regular elements (which have :contents-begin/end)

There is no difference between regular elements and composite elements.
Also, all blocks do not have a value (e.g., center blocks).

> I can see this argument, but I am still unclear on which elements need a
> value, and which don't. For example, src-blocks have a value, but a
> paragraph doesn't, nor do items in a plain list, at least from
> (org-element-context).

In a parse tree, some elements are terminal (i.e., leaves), others are
not. Non-terminal elements have :contents-begin and :contents-end
properties. Others have :value, if it makes sense, or nothing (e.g.,
planning lines).

Source blocks are terminal elements. Paragraphs, lists and items are
not.

Regards,

-- 
Nicolas Goaziou