Re: Bug in new exporter with babel blocks

[Aaron Ecay <aaronecay@gmail.com>]

Nicolas,

Thank you for your explanations, which were very helpful.

2013ko urtarrilak 23an, Nicolas Goaziou-ek idatzi zuen:
> You needn't. org-exp-blocks functionalities are supported by the new
> exporter out of the box.

Can you say more about this?  I looked for but did not find a
replacement to the org-export-blocks variable (an alist associating
block types with functions to export them).  I found it very easy to
hook into the new exporter, but perhaps I missed something?

> Special blocks are de facto, recursive, much like drawers. Their
> contents have to be parsed.

For parsing, yes.  But for export I want a way to say “I don’t care what
Org thinks the export of this block is.  Give me the raw contents, and I
will tell you what the export should be.”

This is how the ditaa special-block code used to work; I see that it has
now morphed into a babel language, which makes some kind of sense.  I’m
not sure it does in general.

My use case is glossed examples for linguistics: my special block
contains three lines, which are a sentence in a foreign language and a
translation.  By inserting markup in a way which is easy to automate,
you can get LaTeX to align the words of one language with the words of
the other.  I don’t want any org processing of the text of the examples:
it might contain backslashes, stars, etc., all of which should be passed
verbatim to LaTeX.  This does not feel like source code, it cannot be
evaluated or tangled, I would not want these blocks to be included in
org-babel-next-src-block, etc.

>> I’d also be happy to discover another, better way of getting the raw
>> text content of the special-block that doesn’t succumb to this
>> problem.
> 
> If you must, you can try:
> 
>   (org-element-interpret-data (org-element-contents special-block))
> 
> from `org-e-latex-special-block'.

I would up patching org-elements to add a :contents property to
special-block elements, which is populated when parsing the original
buffer (and thus dodges the different-buffer-for-export problem).  I can
then retrieve this in my export backend function.  It is a very simple
patch:
-----------cut-here-----------
diff --git i/lisp/org-element.el w/lisp/org-element.el
index 3dc1e72..b67e5e6 100644
--- i/lisp/org-element.el
+++ w/lisp/org-element.el
@@ -1389,6 +1389,9 @@ Assume point is at the beginning of the block."
 			 :hiddenp hidden
 			 :contents-begin contents-begin
 			 :contents-end contents-end
+			 :contents (and contents-begin contents-end
+					(buffer-substring-no-properties
+					 contents-begin contents-end))
 			 :post-blank (count-lines pos-before-blank end)
 			 :post-affiliated post-affiliated)
 		   (cdr affiliated)))))))))
-----------cut-here-----------

Is including support for special blocks that should be exported “raw” a
compelling reason to install such a patch?  I think the only downside
would be increased memory usage/decreased speed for parsed objects
(since they are now storing an extra string), but I think that would be
very small (though I haven’t benchmarked anything).

Thanks,

-- 
Aaron Ecay