Org syntax compatibility with texinfo syntax (was: Org mode and Emacs (was: Convert README.org to plain text README while installing package))

[Ihor Radchenko]

I am forwarding yet another email from the emacs-devel thread to here.
This thread includes both emacs-devel and Org ML.
I will still keep emacs-devel in the loop because people from there can
provide a useful insight about texinfo capabilities.

Richard Stallman wrote:

> I don't know for certain that every possible nesting "does the right
> thing".  I do know that @var{} is used inside many other constructs.
> By contrast, @dfn{} would not be nested inside or around other
> contructs very much.  @key can be nested inside @kbd, and it behaves
> a little differently when nested.

signifying (in addition to previous message), that
1. Texinfo has some software documentation-specific markup elements
2. Those elements can be nested in non-trivial ways, similar to Org's
org-element-object-restrictions, the that nesting can affect formatted
export (again, similar to Org).

With regards to Org syntax, I do not think that we must include all the
possible texinfo elements into Org standard.
@dfn, @key, and @var constructs are extremely specific to software
documentation and have no sense to maintain as a part of general-purpose
markup syntax.

However, what we can do is to allow extending Org syntax to support such
elements. We do support custom syntax elements already (or are
discussing such support):

We have the following, potentially customizeable syntax elements:
- Org links (extensible via org-link-set-parameters)
- Special blocks (de-facto extensible in export backends; also,
  https://github.com/alhassy/org-special-block-extras/);
  
https://list.orgmode.org/87edzqv4ha.fsf@localhost/T/#m6b95119faa65645fd1c32b0e17b6440f73ecd3af
- [FR] Inline special blocks idea being discussed in
  https://orgmode.org/list/87a6b8pbhg.fsf@posteo.net

The links are somewhat limited wrt nesting: links cannot be nested
inside links thus limiting their usefulness as custom markup. Hence, we
may need to look more closely into the idea of inline special blocks
(discuss it in https://orgmode.org/list/87a6b8pbhg.fsf@posteo.net).

Special blocks already support custom :type, but lack convenient Elisp
interface like org-link-set-parameters. (let's keep this part in
https://list.orgmode.org/87edzqv4ha.fsf@localhost/T/#m6b95119faa65645fd1c32b0e17b6440f73ecd3af)

I'd like to keep discussion on the specifics of customizeable Org syntax
in the relevant threads.

In here, I'd like to hear feedback on possible additional
incompatibilities between texinfo and Org. Is there anything (not
covered by the above list) that is present in texinfo, but impossible in
Org?

For starters, Org does not have a full support for generating index
(apart from ox-texinfo and ox-publish). Though see
https://github.com/tecosaur/org-glossary

Best,
Ihor