Re: [O] [ox, patch] Add #+SUBTITLE

[Nicolas Goaziou]

Hello,

Rasmus <address@hidden> writes:

> This patch adds #+SUBTITLE to a couple of backends.  This property is
> already supported in ox-texinfo and e.g. beamer.cls has a subtitles macro,
> but ox-beamer.el has no #+SUBTITLE.  I have used subtitles in
> e.g. applications for research funds.
>
> The value-added is twofold:
>
>     - It adds a consistent way to have subtitle across backends.  I'm
>       explicitly assuming this is nice, but perhaps this is false.
>     - Currently, it is, I believe, impossible to hack-up a subtitle in at
>       least ox-odt.el.
>
> It's not documented yet as I want make sure that it's not an undesirable
> feature before progressing further.
>
> WDTY?

Adding #+SUBTITLE to Beamer is a fine idea, since there's already
a dedicated macro for it. Thank you for taking care of it.

However, I think porting this feature to back-ends that do not support
it out of the box is pushing too hard. 

Back-ends developers should try hard to support features defined in
"ox.el" (in particular in `org-export-options-alist'). However, all
back-ends are free to implement their specific keywords without adding
burden on other libraries. "ox-texinfo" supports #+SUBAUTHOR, should we
add it everywhere? I don't think so.

This is why I suggested to move KEYWORD and DESCRIPTION outside of
"ox.el", as they cannot be ported to all back-ends without relying on
dubious markup.

Now, if SUBTITLE is a feature desperately needed everywhere, which can
be discussed, it should be moved to "ox.el" and probably
`org-element-document-keywords'. IMO, this is not necessary. SUBTITLE
should be kept for back-ends that can handle it.

As a side note, "ox-texinfo" doesn't parse SUBTITLE. You might want to
change it and update manual accordingly.

Regards,

-- 
Nicolas Goaziou