Cusom special block export, similar org org-link :export parameter (was: Org mode and Emacs)

[Ihor Radchenko <yantar92@gmail.com>]

Robert Pluim <rpluim@gmail.com> writes:

>     Ihor> However, we have special blocks for this purpose. They are extendable,
>     Ihor> as I descibed above. Though some improvements in Org core might be
>     Ihor> needed if we have to use this extensibility more frequently.
>
> My first thought here was Org macros, but as far as I can tell they canʼt
> be multi-line, which would make them a bit cumbersome to use. Tell us
> more about special blocks, the documentation on them is a bit sparse.

Macros are meant to configure per-document level of export. Not global,
usually.

Special blocks are Org blocks with the following syntax:

#+begin_environment [optional parameters]
#+end_environment

With "environment" being any word except "center", "quote", "comment",
"example", "export", "src", and "verse".

Currently, latex export directly translates such blocks into
\begin{environment}
\end{environment}

plain text export supports special handling of
environment=justifyleft, justifyright.

html export supports
'("article" "aside" "audio" "canvas" "details" "figcaption"
    "figure" "footer" "header" "menu" "meter" "nav" "output"
    "progress" "section" "summary" "video")
special blocks

texinfo export translates special blocks into
@environment [options]
@end

odt exprot supports "annotation" and "textbox" blocks.

etc.

Because "environment" can be pretty much anything, we can have a
pre-processor in org-export-filter-parse-tree-functions that transforms
different special blocks into appropriate form for a given export
backend (texinfo, latex, ascii, html, etc). This way, we will not have
to rely on backend-specific handling.

Such pre-processor currently does not exist, but it would be fairly
trivial to implement. We may even introduce an interface similar to
org-link-set-parameters for easier configuration of various types of
special blocks.

WDYT?

Best,
Ihor