new LaTeX exporter hook

new LaTeX exporter hook

[Andreas Leha]

Hi all,

the new LaTeX exporter does not seem to "run" the
org-export-latex-final-hook.  Is there an equivalent?

Cheers,
Andreas

Re: new LaTeX exporter hook

[Jambunathan K]

Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:

> Hi all,
>
> the new LaTeX exporter does not seem to "run" the
> org-export-latex-final-hook.  Is there an equivalent?

You are looking for `:filter-final-output' within
`org-export-filters-alist'.

I have defcustom that runs indent-region on final html output.  Here is
the relevant sections from org-e-html together with it's final section.

Adopt this example to e-latex case.

(defconst org-e-html-filters-alist
  '((:filter-final-output . org-e-html-final-function))
  "Alist between filters keywords and back-end specific filters.
See `org-export-filters-alist' for more information.")

(defun org-e-html-final-function (contents backend info)
  (if (not org-e-html-pretty-output) contents
    (with-temp-buffer
      (nxml-mode)
      (insert contents)
      (indent-region (point-min) (point-max))
      (buffer-substring-no-properties (point-min) (point-max)))))

(defcustom org-e-html-pretty-output nil
  "Enable this to generate pretty HTML."
  :group 'org-export-e-html
  :type 'boolean)



> Cheers,
> Andreas
>
>
>

-- 

Re: new LaTeX exporter hook

[Nicolas Goaziou]

Hello,

Jambunathan K <kjambunathan@gmail.com> writes:

> Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:
>
>> the new LaTeX exporter does not seem to "run" the
>> org-export-latex-final-hook.  Is there an equivalent?
>
> You are looking for `:filter-final-output' within
> `org-export-filters-alist'.
>
> I have defcustom that runs indent-region on final html output.  Here is
> the relevant sections from org-e-html together with it's final section.
>
> Adopt this example to e-latex case.
>
> (defconst org-e-html-filters-alist
>   '((:filter-final-output . org-e-html-final-function))
>   "Alist between filters keywords and back-end specific filters.
> See `org-export-filters-alist' for more information.")
>
> (defun org-e-html-final-function (contents backend info)
>   (if (not org-e-html-pretty-output) contents
>     (with-temp-buffer
>       (nxml-mode)
>       (insert contents)
>       (indent-region (point-min) (point-max))
>       (buffer-substring-no-properties (point-min) (point-max)))))
>
> (defcustom org-e-html-pretty-output nil
>   "Enable this to generate pretty HTML."
>   :group 'org-export-e-html
>   :type 'boolean)

Jambunathan is right.  Though, for completeness, I'll add that, as an
end-user, you shouldn't mess with `org-e-html-filters-alist'.  You can
add your filter to `org-export-filter-final-output-functions' instead.

Since this variable is back-end agnostic, your filter will probably have
to check the back-end first. Also, remember this is the functional
counterpart of hooks: the return value of your function will be used as
the new output. Thus, be sure it doesn't return nil.

Example follows:

#+begin_src emacs-lisp
(defun my-e-latex-final-filter (contents backend info)
  (if (not (eq backend 'e-latex)) contents
    ...
    modify contents
    ...
    new-contents))
#+end_src


Regards,

-- 
Nicolas Goaziou

Re: new LaTeX exporter hook

[Andreas Leha]

Hi Jambunathan and Nicolas,


>>> the new LaTeX exporter does not seem to "run" the
>>> org-export-latex-final-hook.  Is there an equivalent?
>>
>> You are looking for `:filter-final-output' within
>> `org-export-filters-alist'.
>>

[...]

>
> Example follows:
>
> #+begin_src emacs-lisp
> (defun my-e-latex-final-filter (contents backend info)
>   (if (not (eq backend 'e-latex)) contents
>     ...
>     modify contents
>     ...
>     new-contents))
> #+end_src
>


Thank you for your input!

Works nicely now (even if the hook system was slightly easier to
use...).

Cheers,
Andreas

Re: new LaTeX exporter hook

[Bastien]

Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:

> Hi Jambunathan and Nicolas,
>
>
>>>> the new LaTeX exporter does not seem to "run" the
>>>> org-export-latex-final-hook.  Is there an equivalent?
>>>
>>> You are looking for `:filter-final-output' within
>>> `org-export-filters-alist'.

Would that be useful to let the filters fall back on existing 
value for ̀org-export-BACKEND-final-hook' and other hooks?

Thus people won't have to change their configuration, plus hooks 
are more familiar to Emacsers.

-- 
 Bastien

Re: new LaTeX exporter hook

[Nicolas Goaziou]

Hello,

Bastien <bzg@gnu.org> writes:

> Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:
>
>> Hi Jambunathan and Nicolas,
>>
>>
>>>>> the new LaTeX exporter does not seem to "run" the
>>>>> org-export-latex-final-hook.  Is there an equivalent?
>>>>
>>>> You are looking for `:filter-final-output' within
>>>> `org-export-filters-alist'.
>
> Would that be useful to let the filters fall back on existing 
> value for ̀org-export-BACKEND-final-hook' and other hooks?

I'm not sure to understand. There is no such hook. Also, there are
differences between filters and current export hooks:

  - filters are applied on a string, current export hooks on a buffer;

  - filters provide the back-end called, current export hooks rely on
    a global variable that has been removed;

  - While run with arguments, filters are not equivalent to
    `run-hook-with-args' since they heavily rely on value returned;

  - filters from users and from developers are clearly separated, which
    allows the latter to always be executed before the former.

Now, as an exception, final output filters could be executed on a buffer
in a hook (by writing the string output to a temp buffer), but since
filters are so common in the new export engine, that extra step is
needed.

> Thus people won't have to change their configuration, plus hooks 
> are more familiar to Emacsers.

  (add-to-list 'org-export-filter-final-output-functions 'my-function)

vs

  (org-add-hook 'org-export-final-output-hook 'my-function)

I'm not sure the difference is worth the hassle.


Regards,

-- 
Nicolas Goaziou