Re: [export] Easy way to make children of Beamer frames generate list items?

[Suvayu Ali <fatkasuvayu+linux@gmail.com>]

Hi Christoph and John,

I'll take an extreme view here.  So apologies in advance.

On Sat, Sep 14, 2013 at 09:40:50AM -0500, John Hendy wrote:
> On Sat, Sep 14, 2013 at 9:28 AM, Christoph LANGE
> <math.semantic.web@gmail.com> wrote:
> > Dear all,
> >
> > here is another problem that I have with reusing old Beamer
> > presentations (Org version 7) with the new exporter.
> >
> > The manual says that "all frame's children become `block' environments".
> >
> > Is there a way of reverting to the default behaviour of the old
> > exporter, which by default exported frame's children as list items?
> > E.g. by setting a certain property on the frame's children?
> >
> 
> Tricky problem, and I could see how this would be an issue. I guess I
> always held to using unordered lists (- blah) for my lists vs. relying
> on the nested headling functionality (** blah). I wonder if you could
> tweak the beamer definition somehow to make a sort of "legacy beamer"
> class for exporting these?

I think it is unwise to keep coming up with ways to support semantically
wrong behaviour just for the sake of backwards compatibility.  This was
changed with good reason and after a lot of discussions.  If you
continue on this path, you will have to keep maintaining this yourself
for all eternity (sorry about the hyperbole :-p).  It's a lot of work
for a long time just to avoid some annoying work now.

> For example, I have the default template in my .emacs from the Beamer
> setup instructions on Worg:
> 
> #+begin_src .emacs
> 
> (add-to-list 'org-latex-classes
>              '("beamer"
>                "\\documentclass\[presentation\]\{beamer\}"
>                ("\\section\{%s\}" . "\\section*\{%s\}")
>                ("\\subsection\{%s\}" . "\\subsection*\{%s\}")
>                ("\\subsubsection\{%s\}" . "\\subsubsection*\{%s\}")))
> 
> 
> #+end_src
> 
> Perhaps something there could be tweaked? I'm no lisp or org -> latex
> mapping person, but perhaps others will have an idea of how you can
> map something dynamically so that "One level below the H:number
> setting gets converted to \itemize" (vs. the current conversion to
> \begin{example} ?

I think the answer is in your response; the template is for headlines up
to a depth n as specified by H:n.  The old (and new) behaviour was (is)
for all headlines deeper than n (n+1 and onwards).  This is
core-functionality, not something that is configurable.

That said, I think converting headlines to lists is not difficult.  You
should be able to define a keyboard macro to semi-automate it.  You can
mark a headline, C-c @, followed by C-c - to convert to a list.
Actually, I think it should be possible to write a custom function to
traverse a buffer and convert all headlines deeper than n to lists using
these same functions.

How about a combination of org-map-entries with a custom function which
does something like this (semi-pseudo-code):

  (lambda nil
    (if (> depth 3)  ; assuming n=3 in H:n
      (progn
        (org-mark-subtree)
        (org-ctrl-c-minus))))

I think you can get depth with something like this:

  (car (org-heading-components))

Hope this helps,

-- 
Suvayu

Open source is the future. It sets us free.