Hello,
Export blocks are blocks dedicated to export back-ends, e.g.,
"#+BEGIN_LATEX". The way they are currently parsed is flawed.
Export blocks are back-end dependent. At the moment, back-ends register
their own export block in a variable, `org-element-block-name-alist', so
the parser can know if it needs to parse an export block or not. As
a consequence, the same block can be parsed differently if a given
export back-end is loaded or not. E.g.,
#+BEGIN_HTML
...
#+END_HTML
will be parsed as a `special-block' if "ox-html.el" is not loaded, or an
`export-block' otherwise. This is slightly... ugly. And it gets worse if
we include the cache, which will not update the block if it is not
modified.
I just committed a set of patches that solve the problem: `export-block'
elements do not exist anymore. Instead, such blocks are now parsed as
`special-block', always. This does not depend on the libraries loaded so
far.
Of course, special blocks are not treated exactly as export blocks. The
latter's contents are included as-is in the output whereas the former's
are interpreted. Therefore, special blocks now include another
property, :raw-value, which stores the pristine initial contents of the
block, and "ox.el" provides a new function,
`org-export-raw-special-block-p', which tells the difference between
a former export block and a special block. This makes sense since an
"export-block" is clearly, and only, an export concept. This is not
related to Org syntax.
This is more simple to handle than it sounds, and can be described with
two steps:
1. `export-block' elements, translators and filters are now ignored.
These can be removed from export back-ends (unless you want to
preserve compatibility with Org 8.2, in which case leaving them
will not hurt: they will be used in Org 8.2 and ignored in Org
8.3).
2. Translators for special blocks, e.g. `org-BACKEND-special-block'
need to be updated and check first if current block is a raw
special block or not. The following template is a suggestion.
#+BEGIN_SRC emacs-lisp
(defun org-latex-special-block (special-block contents info)
(if (org-export-raw-special-block-p special-block info)
(org-element-property :raw-value special-block)
;; Usual handling for special blocks goes here.
))
#+END_SRC
Note that if BACKEND is a derived back-end and doesn't implement
its own special block translator already, there is nothing to
change. The parent back-end will take care of such blocks.
All back-ends in core and in contrib have been updated this way
already.
I included `org-export-raw-special-block-p' in Org 8.2, as
a forward-compatibility measure, so back-end maintainers do not have to
do the `fboundp' dance.
BTW, for those in the back of the room: I didn't remove
"#+BEGIN_LATEX"-like constructs.
Regards,
--
Nicolas Goaziou 0x80A93738
