Re: Emphasis etc. in #+CAPTION:

[Nick Dokos <nicholas.dokos@hp.com>]

Thomas S. Dye <tsd@tsdye.com> wrote:

> I see in the Org Manual that:
> 
>     You can make words *bold*, /italic/, _underlined_, =code= and
>     ~verbatim~, and, if you must, ‘+strike-through+’. Text in the code
>     and verbatim string is not processed for Org-mode specific syntax,
>     it is exported verbatim.
> 
> So a caption like this doesn't export italicized a, b, c, and d
> (presumably because this is a code string):

Hi Tom,

IIUC, it's not because it's a code string but simply because the caption
is not processed for emphasis (or anything else for that matter - see
below). I think the above text in the manual covers the generic case,
but captions were probably added afterwards and they didn't get the
emphasis treatment.

> 
>     #+CAPTION: Pumice collected from pāhoehoe flows at Manini`ōwali:
>     /a/, pieces that sink in fresh water; /b/, pieces without obvious
>     crystallization or coating (Category A); /c/, pieces with obvious
>     crystallization but no coating (Category B); /d/, pieces with
>     obvious coating (Category C).  The scale is 1 cm.
> 
> Is there a common work-around for this that will produce correct LaTeX
> and HTML using the org-mode exporters?
> 

Can't think of any workaround within org-mode. Post-processing the
output to replace /a/ with \emph{a} for LaTeX and <i>a</i> for HTML,
perhaps restricted to captions, seems possible (but ugly).

> And, this is just a question and not a feature request or a request
> for changes to org-mode, would it be hard to change org-mode's
> behavior so that markup like /a/ in the #+CAPTION: string exports
> correctly marked-up text to LaTeX and HTML?
> 

I think this is the way it works currently:

in org-exp.el:org-export-attach-captions-and-attributes() sets  text properties
on the following line (the first line of a table or the line containing a link)
as follows:

        ...
	(add-text-properties (point-at-bol) end
			     (list 'org-caption cap
				   'org-attributes attr
				   'org-label label))

The various exporters then retrieve the caption with something like the
following code (this is one of the three calls in org-latex.el; the
other calls in this exporter, and the other exporters as well, are
similar):

    (let*
        ...
        (caption (org-find-text-property-in-string 'org-caption raw-path))
        ...

This just gets the value of the given text property without further
elaboration. So I'd guess it's possible to change these calls so that
these values are passed through various filters (emphasis is one of
them, but maybe there are others?) before the exporters get them, but it
is not done today.

But maybe I'm full of it, and somebody will come up with a better idea.

Cheers,
Nick