Re: [ANN] Org Export in contrib

[Nicolas Goaziou <n.goaziou@gmail.com>]

Completing myself, I'll add a few notes about the differences between
the current exporter and this one. While it tries to mimic most of the
behaviours of its ancestor, some points just couldn't fit in the new
scheme, would it be for a technical reason or by design.

Here follows a rough list stating how the new engine stands with regards
to the older one.  When possible, the reasons justifying that the
difference remains are given.

1. It's slower.  Indeed, it has to first parse completely the area to
   transcode, even if it doesn't transcode it after (i.e. archive
   trees).  It's the job of the exporter to decide what should or
   shouldn't be exported.  Anticipating filtering would be disastrous
   for some exporters (i.e. the Org one) and wouldn't fit the modular
   design.

2. The document title cannot be obtained anymore from the first line of
   text.  It's either explicitely defined with the =TITLE= keyword, or
   derived from buffer's name.

3. =TEXT= keywords at the beginning of the document are unneeded, and,
   as such, no longer have an effect.

4. "[TABLE OF CONTENTS]" as a placeholder for the table of contents has
   been removed.  Though, a new keyword, =TOC=, achieves the same
   effect, and can even take more values, like "contents", "tables",
   "figures" and "listings".  Tools are provided to make them available
   to any exporter to come.

5. "-t" option at a src or example block isn't supported anymore.  This
   is an HTML only option that could fit in =attr_html= affiliated
   keyword instead, with a "textarea" value.  A new HTML back-end isn't
   available yet, but should develop in that direction anyway.

6. Macros have been under powered a little.  They cannot live anymore in
   comments, example blocks, or even src blocks.  In fact, one cannot
   find a macro where the text isn't parsed.  Macros are Org syntax.
   Using such syntax where there is, by definition, none is just
   nonsensical.

7. For the same reason, invisible targets in comments have been
   deprecated.  For the same result, one can now use a =TARGET= keyword
   instead.

8. =INCLUDE= keyword :prefix, :prefix1 and :minlevel properties support
   has been dropped. Though, the keyword, which doesn't have to be at
   column 0 anymore, is aware about its environment.  If it belongs to
   a list, the whole file will be in the current item.  Also, including
   a file from within a sub-tree will always make the top-level headline
   of the included file is a direct child of that sub-tree.  One
   technical drawback is that no Babel block is executed in the included
   file.

9. Table.el tables will always use their own export back-end.  In other
   words, no Org syntax will be recognized in such table anymore.
   A table.el is an extraneous element while the parser is meant to
   parse Org syntax.  Now, an interesting idea from /Jambunathan K./,
   namely his "list-tables", might fill the gap between the Org
   spreadsheet and the table.el table.  Nothing is implemented about it
   right now, but we're talking about a modular and extensible parser,
   after all.

10. Calling an export function with a numeric argument doesn't change
    headline maximum level, by default.  There are enough ways to change
    this export property already and the argument may be required for
    something more important in the future.

11. =org-export-with-TeX-macros= has been replaced with the more
    appropriate =org-export-with-entities=, and the associated =OPTIONS=
    keyword's symbol changed from =TeX:nil= to =e:nil=.

12. About variables changes, =org-export-author-info=,
    =org-export-creator-info= and =org-export-email-info= have been
    replaced with, respectively, =org-export-with-author=,
    =org-export-with-creator= ad =org-export-with-email=, for the sake
    of consistency with other opt-in variables.


Regards,

-- 
Nicolas Goaziou