From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Goaziou <mail@nicolasgoaziou.fr>
Subject: Re: More export filter examples out there?
Date: Tue, 17 Mar 2015 23:53:48 +0100
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In-Reply-To: <mea93m$s95$1@ger.gmane.org> (Allen S. Rout's message of "Tue, 17
	Mar 2015 18:15:49 -0400")
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To: "Allen S. Rout" <asr@ufl.edu>
Cc: emacs-orgmode@gnu.org

Hello,

"Allen S. Rout" <asr@ufl.edu> writes:

> I'm trying to accomplish a custom export task which I'd hoped to be
> pretty simple:  something like:
>
>
> In each status section, only export the first child headline.
>
>
> After several dumb ideas, I decided that doing it with a filter was
> probably the Right Place.  I built a filter intended to be used on
>
> :filter-parse-tree
>
> and attempted to express:
>
> If you're parent is a headline
> and your parent's title is 'Status'
> and you're not the first of your siblings
>
> then don't be included.  I've added my malfunctioning filter below,to
> clearly display my "thinking".

Untested:

  (defun ox-asr-only-first-status (tree backend info)
    (org-element-map tree 'headline
      (lambda (h)
        (let ((parent (org-export-get-parent-headline h)))
          (when (and parent
                     (string= (org-element-property :raw-value parent) "Status")
                     (not (org-export-first-sibling-p h info)))
            (org-element-extract-element h)))))
    tree)

> I don't seem to be able to get the title as a string.

Use `:raw-value' property.

> org-export-data seems to expect a different 'info' than the 'info'
> present at filter time. I get complaints about
>
> org-export-data: Wrong type argument: hash-table-p, nil
>
> if I uncomment the attempt to string compare the title.

Indeed. One cannot use `org-export-data' during parse tree filtering.
Export output really depends on the tree and the options, which are
being re-arranged.


Regards,

-- 
Nicolas Goaziou